Soldering is easy: twist the wire around what your attaching it to, then drip a blob od solder on it, simple,
or - lots of things these days already have the solder on, in which case twist the end around and heat it up with the soldering iron,
always make sure that there is full contact between the surfaces because solder is a poor conductor.
as for attaching capacitor legs to cases get someone to hold one end of it so the other end is pressing against the case then drop some solder over then 'smooth' it over a bit


tips:

you only have to heat the solder, not wires, connectors or cases,

try to get it done quickly so things dont get hot

easy.

im 15 and i can do it pritty well, if not just get your dad or someone to do it for you, Even your Local Hobby Shop will do it for you if you ask nicely and say you cant solder
soldering irons cast about £15
good luck

Paris