TimothyH's point is spot on. The bikes themselves don't have a lot of tech details or adjustments. The components do. So to find detailed information you look at (for example) your derailleur and figure out the model number or product line. Then you go to Shimano's (or Campy's) site and look up details. If your bike is truly entry level, or if its a Walmart "Bicycle Shaped Object", the components may not be well-known. Look for instructions online, though.
You can also profit from the websites mentioned, or Lennard Zinn's books on road or mountain bike repair.
Is there something specific you want to do with the bike right now?