Shortly, hi and take good care of me.
Well...here's kind of the long and short of it...
Contrary to what some seem to think when they come here, this isn't just one great big roleplaying game. It's a bunch of different, smaller roleplaying games hosted on one site.
So...a good place to start is the Wanted: Players forum. GMs can advertise their games there...it's by no means a complete list of games, but these are the ones that are actively seeking new players. Game ads typically note which system of rules the game is using (D&D 5E, Shadowrun 3E, Star Wars SE, etc...or homebrew or freeform, more on those later), some information about the setting, what kinds of characters they're looking for if they have any limitations or preferences, etc. It's a good place to start looking for games to join, you get a brief overview of the game to see if it piques your interests.
So, you check out a few games until you find one that clicks for you. Simply click on the link in the game ads to go to the game, you can read more in-depth information about the game, about what the GM is looking for, background information, and even, in most games, some of the in-game threads to get some sense of the flow of the game. If the game doesn't appeal to you, no sweat...go back to W:P and keep looking (the game you've looked at will show up on your 'games you currently peruse' list on the site's main page...just click on the "-" in the box next to the game's name if you want it to go away.)
If the game sounds like it's your kind of thing, you want to look at the RTJ thread (RTJ="Request To Join"). The GM will have laid out what they expect from players, what criteria they expect to see met in a request, and any special processes they want you to go through (some will ask for a character name and basic concept, some want a character and at least some basic stats, some want an extensive background writeup...some will ask for a sample of your writing style...some people complain that some GMs have overly stringent criteria for their RTJs, but my attitude towards it is, if you don't like the GM's requirements for the RTJ, you're not likely to care much for the GM's gaming style, either...so I don't complain about RTJs I don't like, I just move on to another game...)
If the GM likes your RTJ, they will add you to the game, hopefully help you finish getting set up, and then you just...play. It's kind of like tabletop gaming, in that you can chime in pretty much whenever the mood strikes you...but other players and/or the GM may get annoyed if you monopolize the game, or if you lag too far behind the established pace of play (if everyone else is posting three times a day and you only post once every three days, the game's most likely going to move on without you.) Most GMs are pretty accommodating to interested players who may not be familiar with their game (for instance, a game I was in, which has gone inactive due to real-life time constraints on the GM, was running with D&D 5E rules...I haven't played D&D with any kind of regularity since before 2E was released, so I needed a lot of coaching on the mechanics of the game.) If you're unfamiliar with the rules and going to need extra help, it's prudent to mention that in your RTJ (in this case, the GM had played another game with me and liked my posting style and the way I played my characters and interacted with other players, so she was more than willing to walk me through getting my character fleshed out beyond the concept phase and help me get through combat rounds, etc.)
If you've joined a game and decide it really isn't for you, simply send the GM a private message and ask to be removed from the game. Most will take care of it right away, and if they don't, you can ask the moderators to do it (after...a week, I think? Someone will correct me if that's wrong.)
Now, regarding Homebrew and Freeform...they're just different categories for games that use unofficial rules (if any rules, although that's extremely rare.) Homebrew typically means that there are a fair number of rules involved, but they are kind of kit-bashed together, a selection of preferred options borrowed or modified from other systems or created out of the GM's imagination. Freeform implies minimal, if any, oversight from the GM, and it's rare that there's a true, totally freeform game out there, where anyone can do anything (although that's the scenario that freeform critics paint in many of their arguments about it). Most of the time, the GM acts as kind of a referee...they define the world, the players move through it at their own discretion, and if they start to take things too far, the GM intercedes. Most of the time, the GM has some kind of a plotline to follow, although there are 'sandbox' games out there where the GM just creates a setting and then remains largely hands-off and leaves the players to their own discretion. It is, perhaps, best to think of freeform games as kind of experiments in collective storytelling, where each player is adding their bit to the story and the GM is basically the primary storyteller and editor. Not everyone likes it, some people love it, some people refuse to go back to playing under a rules system after having played freeform, and some people try it once and never want another thing to do with it again. I think it depends largely on the chemistry of the group with which you try it, but then I'm a firm believer that chemistry will make or break any game, regardless of the setting or system.
That's a lot, I know...but that's the basic ins and outs of RPOL, at least from my perspective. I'm sure others will have their own take on it.
