Rich has lots of info regarding the racks on his website. Here are the instructions for T-stat probe placement: http://www.reptilebasics.com/manuals/dual_rack_inst.pdf
And here is a general FAQ for RBI racks: http://www.reptilebasics.com/rack_faq
If you ever need help with any Reptile Basics product all you need to do is contact Rich at Sales@ReptileBasics.com. He is an expert with each RBI item and is very helpful. I've always had a very quick turnaround on any email I've sent him.