Running Lights install
 

Have a question I am wanting to mount two Harley Davidson Running lights 5" to the pillar Mount on my JK. These are 12 volt lights , My question is what size wire do I need to buy ? Also I was going to go from the Battery Hot side to a toggle switch and then to the lights would I need to put in a fuse in the line also or anything else?

Whenever you add a wire to the battery positive post, install a fuse near that post. The fuse has to be rated to carry more than the load, but less than the wire can safely carry.
It's common when installing lights to control them with a relay. The switch carries the low amperage of the relay coil, and the relay contacts carry the higher amperage of the lights.

Regarding wire size, it depends on the amperage of the load, and the length of the run. There are many wire load charts on the internet.