Here are the components that come with your purchase of a Predator MousePad Attachment (MousePad Attachment Plate included, but not shown here). Colors will reflect your selection at purchase. 

(1) Horizontal Attachment Beam, (2) CrossBeam, (3) L-Bracket w/ pre-installed double t-nuts and screws, (4) three [3] Anchor Fasteners, and (5) Attachment Plate Mounting Kit, consisting of two [2] t-nuts and two [2] 3/8" length screws. Now let's begin!

After conducting a quick inventory of all your components, locate the CrossBeam, the 5/32" allen wrench, and the L-Bracket (with pre-installed t-slot double nuts and screws.) Hold the CrossBeam with one hand, and with the other hand, insert the L-Bracket into the BOTTOM t-slot channel (this will be the channel OPPOSITE of the countersunk hole for the top-side anchor fastener). 

Slide the L-Bracket to the edge of the CrossBeam like shown in the top right picture above. Make sure the edge of the L-Bracket is FLUSH with the edge of the CrossBeam. Tighten down the two screws to secure the L-Bracket to the CrossBeam. Next, locate the anchor fasteners (You have three anchor fasteners, but will only need two of them right now. Put the third one to the side). To determine which slot the two anchor fasteners will be inserted inside, hold CrossBeam with one hand. If you intend to install the MousePad Attachment on the LEFT HAND SIDE of a mount, point the "L" of the L-Bracket to the RIGHT. The channel that is facing you is the channel you will insert the two anchor fasteners into. If you are mounting the attachment on the RIGHT HAND SIDE of a mount, point the "L" of the L-Bracket to the LEFT. The t-slot channel that is facing you is the slot you will insert the anchor fasteners into. 

You will insert BOTH anchor fasteners into the same t-slot channel (see the above right picture.) Insert the first anchor fastener with the SMOOTH FACE DOWN. Insert the second anchor fastener with the SMOOTH FACE UP, just like in the above right picture.  

Hold the CrossBeam in one hand, and point the end with the L-bracket away from you (see pictures above). This is what you should be looking at. If you are installing the MousePad Attachment on the LEFT SIDE of a mount, you should see the same thing as the left picture above. If you are installing the MousePad Attachment on the RIGHT SIDE of a mount, you should see the same thing as the right picture above. 

Locate the Horizontal Attachment Beam and the two (2) t-nuts. It does not matter which side you choose, as long as it has two (2) t-slot channels on that side. Insert the t-nuts into the Horizontal Attachment Beam (see pictures above). Let them slide all the way to the bottom. The plastic endcap will catch them and stop them from falling out.  

Locate the CrossBeam (with the L-Bracket and two [2] anchor fasteners in a t-channel slot) and the Horizontal Attachment Beam that you just inserted the two t-slot nuts into. Without letting the t-nuts fall out, hold the CrossBeam like in the above left picture, and separate the two anchor fasteners, so that you have enough room in between them to insert the Horizontal Attachment Beam. (See pictures above) It's easiest if you hold the CrossBeam with one hand, slide the anchor fasteners apart with the other hand, and insert the Horizontal Attachment Beam in between the two anchor fasteners just like in the picture above. You should have a "T" structure like shown. 

Slid the Horizontal Attachment Beam all the way to the plastic endcap and push the anchor fastener in the countersunk hole (See above left picture) Tighten the anchor fastener down. Now slide the other anchor fastener into the countersunk hole on the opposite side of the Horizontal Attachment Beam and tighten down (See above right picture). 

After all that hard work, this is what you will have created, the Predator Attachment Frame. You should have one (1) anchor fastener, two (2) of the 3/8" long buttonhead screws, and the MousePad Attachment Plate (not shown here, but it's the big, black, powder coated plate that came in the box). 

After you've assembled the Predator Attachment Frame, you need to connect it to your mount. Follow these instructions to complete the assembly of the Predator MousePad Attachment. 

(Note: You will need a 5/32" allen wrench to complete the assembly of the Predator MousePad Attachment, by attaching it to a pre-existing mount of your choice. This attachment will connect seamlessly to all Predator Desk/Table Mounts and FoxxMount Desk Mounts. (This attachment will also attach to most other mounts that utilize a 10 series aluminum extrusion frame.)  

With the 5/32" allen wrench, remove the top plate of the mount that you will be installing the MousePad Attachment on. Place the screws and mount top plate to the side, as you will need these components again. 

Take the Predator Attachment Frame that you just assembled, and insert the L-Bracket into the left/right side of the mount. (See above left picture -left side mounting shown here) that you configured your Predator Attachment Frame for. Once you have inserted the L-Bracket into the vertical beam of your mount, move the CrossBeam up or down the vertical beam of the mount to the desired height. (You can always do this step at the end of the installation). Use the 5/32" allen wrench and tighten down the two screws in the L-Bracket to the vertical beam of the mount. (See right picture above). 

Locate the last anchor fastener and insert it into the same t-slot channel that you inserted the L-Bracket into (see left picture above) After you've inserted the anchor fastener into the countersunk hole on the top side of the CrossBeam, use the 5/32" allen wrench to tighten the anchor fastener. This should finish pulling the CrossBeam entirely snug to the vertical beam of your mount (See right picture above) 

Now that you've successfully attached the Predator Attachment Frame for the MousePad Attachment, locate the top plate and screws that you removed from the mount before installation of the frame, and use the 5/32" allen wrench to connect the top plate back to the mount (use the same screws you took off with the mount top plate). After you installed the Mount Top Plate back onto the Desk/Table Mount, go ahead and clamp it to the Desk/Table that you had it originally clamped to. Take the MousePad Attachment Plate, the last 2 screws that came with the package, and the 5/32" allen wrench, and install the MousePad Attachment Plate like in the pictures above. You're finished product should look like the picture on the right. You are finished with the installation of the Predator MousePad Attachment! 

(NOTE: Your Predator MousePad Attachment has the ability to adjust 4 different ways: UP/DOWN, LEFT/RIGHT, FORWARDS/BACKWARDS, and SWIVEL. For best results, only adjust ONE aspect at a time, i.e. adjust the height of the MousePad Attachment by loosening the top-side anchor fastener in the CrossBeam, then loosening the 2 screws in the L-Bracket that connect it to the vertical beam of your mount. Slide the Attachment up or down to the desired height, and re-tighten the L-Bracket and top-side anchor fastener. When adjusting the MousePad Attachment, adjust only ONE aspect at a time, for the best result)