Per the user instructions accompanying your Slide:
1. Before removing the End Cap, slide the Blade in the outermost channel forward approximately halfway. Otherwise, the End Cap is locked into place (to avoid having it come off in your pocket).
2. Take off the End Cap by pressing either of the small rectangular cut-outs located on either side of it.
3. To remove a Blade, simply slide it completely out of the channel. To insert a Blade, depress the Node and guide the Blade into the selected channel.
4. To reattach the End Cap, slide the adjacent outermost Blade forward, and hook the End Cap to the opposite side latch. The press the End Cap on and retract the outermost Blade.
You can also view the Keyport Slide 2.0 Instruction Guide.