If you really want to learn a mess of information about steroids, I'd suggest getting a book. While places like this are good for learning "rule of thumb" ideas, a lot of bad information floats around because people are just misinformed.
You might be under the impression that estrogen is bad, DHT will make your hair fall out, and you have to suppress all of these things. Well -- that's only a half truth, because in reality, estrogen is anabolic, and you actually want your testosterone and nandralone based anabolics to undergo a 5 alpha reductase (enzyme responsible for converting test into DHT) once they are inside they cytoplasm.
One book that I could recommend is anabolics 2004. I've got 2002, and there is a shit-load of chemical analysis, and extensive citation of clinical research. The guy knows his stuff. There is an in depth analysis of over 140 compounds, stacking suggestions, side effects, and the whole 9 yards.
Like I said, there are a lot of people here that really know their shit, and they have it together. But then there are many who don't, but offer up their opinion anyway. Take it for what it's worth, but my experiences have been best with professionally published materials.