To build the Three Fives kit, basic electronic soldering skill and tools are required, but no additional knowledge of electronics is presumed or required. You provide standard soldering tools: a soldering iron + solder and small ("flush") wire clippers, as well as a Phillips head screwdriver.
The Three Fives circuit is a direct implementation of the "equivalent circuit" from the NE555 datasheet, built up using resistors and individual 2N3904 and 2N3906 transistors. It comes with terminal posts and solder points so that you can actually connect to it and build up classic 555 timer and oscillator circuits. Using those terminal posts and solder points, you can hook up with with bare wires, lugs, alligator clips, and/or solder joints-- however you see fit. And unlike the chip version, you can even hook up probes to monitor what goes on inside the circuit.