First off you need somebody that understands how the game works on paper. If you want to read up on it you can be that person (also there's a more basic version of the manual available at <a href="http://dnd.wizards.com/articles/features/basicrule" rel="nofollow">http://dnd.wizards.com/articles/features/basicrule</a>... ) or you can find a friend to help out. Either way you will want to make it through rolling at least one character, though it's good to have some familiarity with most classes if you're going to DM for a game. To use roll20 for the game that person should also check out the roll20 tutorial, just so they recognize how the virtual environment works and what they can generally do with it. These are the only necessary steps. At that point you need to have somebody to DM and at least one player, though 4-6 players is ideal. Optionally you can import a lot of custom material and macros to give yourself some one click options instead of having to type commands into the chat window. As for your version of the player handbook- Don't read it cover to cover. Most of the rules for how the game works are in chapters 7-10. The intro and chapter 1 can give you a good idea of what's going on, then those four chapters go into all the broader game details. Chapters 2-6 are character choice stuff and a lot of reference tables, and chapter 11 lists all of the default spells that some classes can cast. It's pretty painful trying to read through chapter 11 since that's more like a dictionary, and the character stuff is all kind of split between some descriptions of what any of these things are in a fantasy setting and then more little dictionary/ability sections. And then there's like 30 pages of fluff at the end with a few useful reference pages. If you're creative and can come up with something you want to do you can be a DM with just what's in the player's handbook, but it lists very few monster stats. There's a monster manual book that's useful for adding basic variety to combats that any DM will probably need. The Dungeon Master's Guide is roughly half fluff and overview, almost half magical item index, and a few pages with other kinds of tables and rules that you'd ever need to reference. Still useful, but fewer tools than I expected when I was waiting for them to publish it.
