Unsure about skills and spells

New to POE and was wondering if I use a skill like Cleave with Arcane Potency (Increased critical strike chance for spell and increased critical strike multiplier for spell) will I get higher crit chance and damage on cleave?

Or will increased critical strike multiplier and increase critical strike chance give me more crit chance and crit damage?

I'm unsure how skill gems and spells correlate basically

On the same notion will more spell damage increase the damage cleave does?

On wiki it says that "Spells are skills which do not draw their damage from your weapon in any way." Still not sure after reading that.

Ty for any clarification.