once you've gotten your balance and are familiar with the brakes, take your bike for a 1 mile ride, when you can do 1 mile then do two and so on. Once you hit five miles you may want to find that you want to do more one mile extra so try a 10 miler. After each ride evaluate how long it took, how you felt and what could be improved. Ask for help, there are loads of knowledgeable riders here and the only stupid question is the one you don't ask. Also bear in mind that your are on the bottom of a steep learning curve, the more question you ask, the more you learn and the more questions there are. Remember to mentally evaluate each ride and log your rides by time and distance- you'll be amazed.

welcome to the big adventure or the thin edge of the slope, however you choose to look at it.