I've played a lot of DnD and the most important thing as a new player is finding where your vibe is and working it into the table. I currently DM two groups. One group is very into playing characters, and the other is very into playing the game DnD (we actually switched to Pathfinder once that became apparent to me). What I mean by that is the first group likes to have long dramatic conversations with NPCs that develop character motivations and such, and will often go entire sessions without combat, which is great. The other likes to scour rule books to build really interesting characters and then use those really interesting characters to kick total ass in a tactical combat simulator. For them, battle mechanics are a method of getting into character, and the plot and personality, while still important, play a supporting role to Doing Cool Shit like lassoing and riding mammoths, which is also great. Neither of these groups have "actors" in them, in the sense that they'd probably be really uncomfortable at a CR table where people are doing voices and such. I only rarely do voices, although a GM can do a lot with just speech patterns.

Point being, there are tons of ways to play DnD and no correct way to do so. You need to explore the different play styles and find what you like to do. When I play, I like starting with a mechanical concept and building my character's personality and story around that. I.e. this character is really freaking good at Linguistics, but why? Well, they were training to travel throughout the planes as a diplomat of Axis before tragedy struck and had to know two dozen languages, etc.