Brand New to the game

Using d20Pro when you're first learning would probably be a terrible crutch honestly. It automates enough that you probably wouldn't internalize and really learn the rules. Depending on what edition you're using (I assume either 3.5 or Pathfinder), the best start is probably by reading the Player's Handbook (Core Rulebook for Pathfinder), beginning with the Combat chapter, followed by Skills, then Feats (you don't have to read up on every skill and every feat, just the beginnings of these chapters, as they spell out how skills and feats work). Follow that up by skimming the Classes and Races chapters.

After reading those chapters, I'd suggest making a few characters. Both the 3.5 and Pathfinder books have good character creation checklists at the beginning of the books. It's a good idea to start with something like a fighter or a rogue. If you feel you've got a good grasp and feel adventurous, try a ranger, paladin, or barbarian. You generally want to stay away from casters for your first few characters (not a hard fast rule though). Whatever you do, you're going to want to read the ENTIRE entry for whatever classes and races you make characters from.

After that, you're ready to start playing with a group (and probably far more prepared for it than most people are during their first game). If you can, you DEFINITELY want to play for a few months before you try your hand at Dungeon/Game Mastering. If you've done the reading and character creation practice I suggested, playing with a group via d20Pro wouldn't be a terrible idea, whatever gets you playing honestly, but if you can, it'd probably be better to play with a local group using regular paper character sheets and dice. As I said before, d20Pro automates enough that it would fight against your internalizing of the rules that you need at this point. So if you do end up playing using d20ro, I'd suggest re-reading the Combat chapter (at least) every once in a while.

After a few months of playing, if you feel comfortable, you could start reading the Dungeon Master's Guide (or the Gamemastering sections of the Pathfinder Core Rulebook) and running your own game. Unlike playing though, Game Mastering is very much something that you can just kinda jump into, and is probably the best way to learn it. The important thing with game mastering isn't the rules, it's the story telling. You can learn the "proper" way of arbitrating rules as you go along. This is probably the point you'd want to start teaching your kids, and they could be the first group you Game Master for.

Anyway, that's my personal advice, from 17 (almost 18) years of playing this wonderful game. Honestly though, whatever feels comfortable for you is what is right for you.