Create a character using the DND 5e classes and races with a short backstory. You will play as that character for the duration of the game. The setting is (usually) high fantasy with elves and magic and dragons, etc. We decide as a party what we want to do, and the Dungeon Master (DM) guides us along a path for a story to occur. Whether we follow it loosely or strictly is up to the DM. Every now and then there will be battles in which we+the enemies roll for initiative which determines the battle order, and then we fight enemies in a turn-based system. Once we win, we can get gold, items, weapons, and experience which will make us stronger. After all that, it's mostly just fucking around with the world in character and doing Fun Stuff. Lots of freedom to be as smart or dumb as you want.