There are several ways to connect add-on circuits or repair damaged wiring. The hardware you see here is NOT how to do it. The white and blue plastic wiring tools are called insulation displacement connectors, or more commonly by the 3M brand of Scotchlok. They have no use outside of an emergency or temporary installation in a location that will not see rain/dirt/snow. The small brass terminal is called a fuse tap and is designed to slip over an existing blade fuse to allow an additional wire to be added on. These things usually damage the terminals in the fuse box when used. Learning to properly connect, crimp, solder, and shrink wrap wiring with quality terminals (not the 1,000 pieces for $4.99 garbage) is a must for any enthusiast.