There are a lot of techniques out there -- hooping only the stabilizer then spraying the stabilizer with a spray baste and attaching the fabric to the stabilizer keeps the fabric from stretching too much. I have done this with a water soluble and lightly sprayed the fabric. A further anchor with a couple of pins.
The idea is to keep the embroidery from bunching up the fabric. I have also done a lightweight fusible with a water soluble in the hoop (I tend to stretch my fabric too tight if I put it in a hoop).
My advice is to play. Get small amounts of various stabilizers and play -- don't be afraid to use more than one stabilizer layered. Figure out what works best for you and your machine.