Title says it all.
I don't understand +, - and GND - what do you imagine powering this with? L
A small tesla coil.The + Goes to the + on the battery pack and the - goes to the - on the battery pack, and the GND is the Ground.
What is the GND connected to, other than the circuit? L
A metal pole in the ground.
It's isolated from = & - then? I don't think that would work. L
"-" and "ground" are usually the same thing.