abslution

@HarryPotter1025 
            It's kind of writing a story but you are only one person [or however many you've signed up for - sometimes people let you have more than one]. I'm sure if you sign up to one and see what other people are doing, you'll quickly get the hang of it. Just remember to read any rules and things that the author has set. 
            
            I hope that's helped. But if you have any more questions I'll be more than happy to answer them.

@HarryPotter1025 
            It's easy once you know the basics, I suppose.
            You can sign up to someone's roleplay, usually you get the option to be either a pre-existing character [a character from that particular book/film/TV show/etc] or an original character [aka OC - a character you've made up] 
            To make an OC, you will probably have to fill out a form that the author of the roleplay has given. So just fill it out in the comments and post it.
            Alternatively, you can ask to be one of the pre-existing [or 'canon'] characters if they haven't already been taken by someone else.
            After, just wait to be either accepted or denied [most likely accepted], then go to one of the tabs.
            Usually the tabs are locations where you can pretend to be like mine are, or the  tab will just say 'roleplay' or something where you can just begin with no specific location. 
            Most roleplays will require you to actually roleplay in third person. So all you do is type out a little parragraph or a sentence or something that has your character do something or say something or whatever. But you must only control your character otherwise it is seen as what we call 'god playing' or 'god modding' and people get annoyed.
            Let me give you an example. Say I'm Remus in marauders-era;
            'Remus arrived in the Gryffindor Common Room, fatigued after the transformation that just occurred. He dragged his feet as he sluggishly sauntered over to the sofa.'
            Then someone else might reply. Say they're Sirius;
            'Sirius followed him in. He was quite the opposite to Remus; full of energy and quite frankly hyper. He went over to Remus and gave him a pat on the back, "Well done, pal!".'
            And then either I could reply again or someone else could, say someone else is playing James. And so on.