Group of EXTREME noobs that need help and guidance

Allow me to introduce myself. I am VERY new to table top RPGs. I've played a little of Dungeons and Dragons, (though I doubt we were playing properly) and I absolutely loved it. And I, being the weirdo that I am with no real life friends, decided to try to play Dungeons and Dragons with my friends through this Roll20 service. However.... I don't understand a thing. I do not know the first thing about Dungeons and Dragons, and the first thing about using this service. I am a very visual learner, so the tutorials and guides for either this service, or D&D in general, make no sense to me. I'd like to learn the ropes of using this service, as well as D&D, so I can pass it on to my friends. If there is a way anyone can help, please do!

Hello! I'm Kir! I've been playing tabletop for 15 years, what are you looking to learn just 3.5 5th? Pathfinder possiblly?

Hello Kir! I guess I'd want to learn 3.5, because 5th sounds newer, (and newer sounds more complicated) and I have NO idea what Pathfinder is...

5th Edition is actually more simple.

As someone that knows both 3.5 and 5th edition of D&D, I would most certainly say that 5th is much more streamlined and easy to understand than 3.5. To facilitate finding someone that can guide you, how about you post your timezone and the amount of friends that want to play?

Oh really? Who would've guessed! Then I guess I want to learn how to use 5th edition then. And one quick question before we get too far, can the GM have a character of his own to participate in the story, or is it against the rules? I would understand how it could be unfair, but there are only three of us, so I would like to participate with them.

Oh, and my timezone is Mountain Time, (UTC - 7:00)

You can have an NPC in the party, it's just not a great idea (especially to begin) they tend to know too much or be suited to kill things in the campaign. Basically you dont want to steal your players thunder. I'm a mountain timer myself!

Well the GM gets to control all the characters in the game that the players don't. so the GM plays the  town folk, villains, monsters, and any thing else in the game. So technically you get way more characters to play then the players. However you dont need to make a character sheet for every townsfolk just have some data on things they are going to fight. But with that said there is no reason you cant have a character in the world that traels along with the players just with all the rest of the stuff to take care of sometimes it can be to much. There are also different opinions on if its a good idea or not. The main one is it might take the spot light away from the other players. That however is a dependent on the group you are playing with.

Hm... I doubt my friends would care. They are really chill, and I wouldn't steal their thunder. I would be fair with it, and not make myself an unstoppable badass. Glad to know your opinions on it!

I've just seen the good the bad and the ugly of it. 5th edition is a bit about background and ALOT about proficiency

another trick you could do if the other players where up to it is known as "Town bicycle" you run a short adventure then some one else runs one in the same world influenced by the things the players did last time. This lets every one get a turn being a player. or a hero academy where you can all have different characters and they can get sent out on quests run by different DM's.

So, I know the basic rules for Dungeons & Dragons, the biggest questions I have are the specifics of combat, and how to use maps and such, because the group I used to play with did it all in our heads.

alright, ask away. 5th is a little different then 3.5 but overall it works the same.

So, Is there a difference in gameplay when using visual maps and representations? Or is it just that, a representation? Nothing more, nothing less?

the combat stays the same between the two, maps just give you a representation and a method to gauge distance.and the like.

Yeah I thought so. I knew it was a stupid question but I just wasn't sure. Now, on combat... How does it work exactly. I know that a character has a hit dice and such, like 1d8, but how do you determine turn order, and how do NPC actions work?

Turn order is generally determined by Initiative rolls.  NPC actions would be handled by the DM and as far as I can tell really don't vary TOO much from any normal character.