That’s probably one of the most common places for new players to get caught on because of how different Dungeons and Dragons is when compared to other games. Although D&D has a lot of rules (several books worth of rules at that) and seems very daunting to start fresh for new players, D&D is possibly one of the easiest games to actually play.
The first thing new players need to understand is that D&D’s rules are not so much “rules” as much as they are “guidelines”. As important as the rules are, there’s no reason to limit yourself to what the books say you can do. Kinda like the Pirate Code in the Pirates of the Caribbean movies.
Every single rule in the game can either be removed, replaced or reworked into something else. The game is about creativity and imagination, not following rules to the letter. Video games or board games have very strict rules because otherwise the game doesn’t work, but in a game like D&D the point isn’t to beat the objective while following the rules of play. Instead, you want to overcome obstacles in whatever method you see fit.
Imagine a dragon blocks your path and you need to get past it. Do you attack it head on while wearing heavy plate armor and a massive two-handed sword? Do you try and sneak your way past by hiding in the shadows? Do you use the numerous magical spells at your disposal to turn the dragon into a frog? Or do you come up with another idea that combines the random items in your backpack to cobble together something no sane person would attempt and then you roll a Nat 20 to trick the dragon into accepting it as a gift to let you pass?
The answer is whatever you want to do.
So when you decide to play D&D with your friends and you’re worried you don’t know exactly what you can do, don’t worry. There is nothing you can think of that you can’t do in game. Everything has a chance to succeed or fail, the fun is finding the best way to increase your odds and lower your enemies’ at the same time.
Sure the rules are important since you’ll want to understand the basics of how the mechanics interact with each other (like what bonuses to add to your rolls and how to increase them) but really the game can work just as well without any rules and just your imagination.