Let's start by measuring three pieces of 26AWG silicone cover stranded-core wire to approximetly 11cm in length. We'll also need three pieces of heat shrink tubing.
Prep wires for slide switch
Strip off the ends of each wire using wire strippers. Secure the wire to a helping third hand. Tin the ends of each wire with solder - this will join the strands together.
Each wire should have ends stripped and tinned with solder. The colors are nice and help tell connections apart but it's not required - use what ever you have.
Place the slide switch into the Panavise Jr. with the terminals facing outward.
Solder wires to slide switch
Secure a wire to the helping third hand and position it close to the terminals on the slide switch. Solder the end of wire to terminal. Repeat this for the other two wires and terminals. Ideally you want the red and white wires on the outside - green in the middle.
Heat shrink slide switch
Apply hot air to the heat shrink tubing to secure the exposed soldered wire connection.
Wire slide switch to Powerboost 500C
Mount the powerboost 500C to the panavise Jr. Insert a wire to END and the other to GND.
Solder wire connections and remove the excess wiring from underneath the PCB with wire cutters.
Ideally you want to use longer female/female or male/female jumper wires. 40 x 6" is suffice but the 3" may be too short. In my case I only had shorties so I combined two wires together to make longer cables.
Break off two pieces of jumper wires and cut off the ends from each wire, leaving just one female jumper connector. Strip the ends and tin with solder.
Insert the tinned ends of the jumper wires into the postive and negative pins on the Powerboost 500C. Solder wires in place.
Carefully wrap the 2500mAh lithium polymer in gaffers tape. This will allow for more protection on the surface to prevent it from being punctured.