The main thing is you are working in the back loops for the whole thing, NOT going into the posts/bars.
I always start any crochet by crocheting in the back loops. I like to leave the braided edge of the chain untouched, it looks better IMO. So draw up your loops through the loops in the back of your foundation chain.
Hook them off just as you would with regular Tunisian crochet drawing through 2 lops on hook. the only thing, when drawing up your loops it is VERY EASY to drop the last stitch so you gotta make sure you don't loose it.
As you can see, like traditional Tunisian Crochet your stitches are locked together with the loops. But by going into the back ridges it spaces the rows apart quite a bit creating a mesh like fabric. This is the front of the small swatch I made for these photos