Need help on my first t-shirt quilt. Do I put the waxy side of the freezer paper on top of the fusible interfacing when re-enforcing my t-shirt block?

You shouldn't need it at all ( the freezer paper ) as long as it's only got the fusible on one side of it. Since the fusing will be against the t-shirt the other side is just plain fabric.

Okay, so I really don't know what I'm doing. I will have fabric on the back of the block and then add backing on the whole quilt?

The first thing you do is to cut the tee shirts bigger than the finished block size. I am very generous with the size like several inches larger than the finished size. Then you fuse a fusable interfacing to the BACK of the tee shirt. I like to place a teflon pressing sheet on teh ironing borad, then the tee shirt FACE DOWN, and the fusable interfacing glue side down on the back of the tee shirt. Then fuse them together. The teflon sheet helps the heat from the iron fuse the interfacing better and any design on the tee shirt will not stick to your ironing board cover. Then and only then...cut the tee shirts the size blocks you want to use in the quilt. You may add sashing or not, that is up to you. Tee shirts stretch and the interfacing will stop them from doing that. It is a very necessary step. Most long arm quilters will not even attempt to quilt a tee shirt quilt unless it has been stabilized. No need for freezer paper at all. You can PM me for more help if you need it.

here is a tute from missourri quilt co.

http://www.youtube.com/watch?v=JE3jqR2N4KA