Most actions like lock picking, first aid, and speaking foreign languages that require training to learn must be listed on your sheet. Actions like driving, climbing, and brawling that are really easy can be accomplished without them being listed, but they are more difficult. A narrator or storyteller will determine the difficulty of most of the things you will do. If you win, you're successful, if you lose your attempt fails. Ties are a little tricky, but you'll get the hang of what will happen fairly soon.
Some events have pre-generated characters, some involve characters generated by the players.
Characters improve over time, and can learn new abilities and gain powers. The amount you can improve is up to the storyteller. You can use these experience points to improve your character in extended games. Generally sure, with permission from the Storyteller. Just don't get too attached to your character.