There's a really wonderful tutorial on Coq [1] that holds your hand through all the theory you need to learn. I took a class that used this tutorial and I found it to be very understandable and practical, with hardly any background on formal methods myself. Yes, it's a steep learning curve, but at least with this tutorial, you know the curve you need to follow.

[1] Software Foundations http://www.cis.upenn.edu/~bcpierce/sf/

Hint: Check out the overview [2] to see the chapter dependencies and decide which chapters you may want to skip.

[2] http://www.cis.upenn.edu/~bcpierce/sf/deps.html