It does take playing around with it, but there is not really a right or wrong way to do it. I guess the only caution would be not to roll your lumbar spine. Otherwise, just find a way to get your bodyweight on the tight spots. If it's a knot, just rest on it until it begins to release. If it's just tight and feels good to move on it, then roll back and forth.
It does help to have some pictures of how other people use it though. I agree with that. Eric's article is helpful. Here is another roller guide that has a lot of pcitures you might find helpful.
Roller Guide