I will be overwintering my plants in an unheated garage any and all info/ links will be much appreciated thank you.

Will the door stay closed. I would definitely keep them off cement floor. just set pots on boards

Yes the dorm will be closed and okay I will keep them off the floor. How often should I water them?

Based on my experience, my unheated garage lingers around 50°F throughout the winter, give or take 5°.
I'll give a 1 gallon pot about 8oz of water every 3-5 weeks.  You really need to base this on weight and moisture of the pot to determine if they need water or not.  The thing to remember is not to let the root ball dry out.  You just need a LITTLE bit of dampness in the root ball.  Do not let it sit in a soaking pot when dormant, as root rot may occur. 
Light is unnecessary when a tree is dormant.  They can be in pitch darkness all winter as long as there are no leaves.

Wait really? The trees can survive with only half a bottle of water a month!?

Yep. The trees aren't using any water while dormant. Some people give zero water and the trees come back to life in the spring.

Ooh okay cool thanks