New to Roll20 or RPGs? Need Guidance? Click Here. (Read the OP First)

Welcome Francesco! To your first question, it depends on the game system. We have community created character sheets for many systems at this point, but if you're playing a lesser known game, there might not be a character sheet created for it yet. It does depend on the sheet designer, but a lot of the sheets are automated and will change dynamically if you alter stats. Roll20 has no built-in bestiary or rulesets. It's system agnostic, so it'll allow you run pretty much whatever you want and use whatever house rules you and your group would like to use.

TheInfamousNerd, first step as a newcomer to tabletop RPGs is familiarizing yourself with what games are available. Dungeons and Dragons is one of the most popular game franchises, but it is not the only RPG on the market now. D&D also has several different editions where the rules are different between each edition. If you want to play D&D specifically, figure out whether you want to play with the 4th Edition ruleset, or 3.5 or the brand new 5th edition, etc. etc. These days, you can find any game or ruleset for any genre or fandom franchise which vary from light rules to very comprehensive rules that can cover several expansion books. Whatever game you do end up going with, pick up a copy of the player's handbook or core rulebook and read through it to familiarize yourself with that game's rules. Once you got a grasp of the rules, go to our LFG (Looking For Group) tool and search for games that are looking for players running the rule system you want to play. The GM of the games you send applications to will tell you how they want you to create your character and will help you get situated. Lots of games run in LFG are newbie friendly.

Tigra, most games in LFG, unless they're board games, tend to be set in the future and not match making for gameplay in the present. That's typically to give the GM enough time to figure out who's a right fit for their campaign and for the players to put together their character sheets. Each GM is going to have different prerequisites in how this is done. Jacob, what sort of trouble are you having with LFG?

Roll20's drawing tools don't behave like MapTool's. There are no texture brushes and when you're creating the backdrop, nothing ever flattens out on Roll20. Each illustration stroke will be its own object. MapTool uses raster graphics (Think Photoshop) while Roll20 uses vector graphics (Think Illustrator). If you plan to hand draw your map in Roll20, you might end up with many drawing objects sitting on your tabletop before you start placing tokens down. It's recommended that you draw a battle map in another piece of software like GIMP or in Maptools itself and bringing the finished image back into Roll20.

Jared, that sounds like a bug. I'd recommend creating a seperate thread in the Bug Reports forum.

Is your friend the GM? If so they should guide you through the character creation process. GMs typically want their players to draft their characters in a very particular way.