Well, if you're just starting with rebuilding:
Check out YouTube for some instructions. Its simply a better way yo learn than trying to read instructions.
You'll want 28g and 26g to start probably. Additionally a good pair of nail clippers, a coil jig, and an ohm meter. The kuro concepts coiler or coil master are both life savers.
@Countrypami gave you a good link for a calculator.
If you're using a subohm tank then yeah, a 0.5-0.6 would be a good starting point, if you're using a nautilus or something above 1ohm, I would say start with a 1ohm coil.