I use the same stuff you got...Some people smash them up a little...personally, I use them as is. VERY IMPORTANT! You must rinse and rinse and rinse and...rinse again until no red dust water remains.
fill bottom of pot 1-2"deep and fill in with good potting soil leaving enough depth for your plant...place in plant and backfill.

what kind of soil are you using. This is important. If you mix yourself there are good ways and bad ways...so let us know...peace