Im thinking Sicilian Defense.
I would like to improve in chess so I need some advice!

I want to learn about chess. Anybody here who can give me some tips please
Find a YouTube channel like GothamChess and watch one of his begginer series videos.

If you need help getting better at chess, i'd recommend looking at the "Learn" section, there's articles, videos, lessons, openings, and an explorer so you can check out moves and games, and how good the moves are. They're all limited to free users, usually # per day, but after leaning a few lessons go look at Puzzles next, and try out some of the daily puzzles. Play and watch live chess to get better and learn some new things. the more you learn and practice the better you get. Good Luck!
The Four Knights typically involves the move e4, not just the Knight moves. The typical Four Knights would look something like this:
This is a common approach, especially for new players because it develops their Knights to where they are trying to move, and it develops their pieces without undue complication.
The Four Knights is playable, but whether it's 'good' or not depends on how you follow up with it. At a basic level, it's acceptable, but it's not typically a highly aggressive opening that will force the issue. So whether or not you play the Four Knights isn't necessarily a central matter, and it might be more prudent to focus on your awareness of tactics and familiarity with the pieces.
you are lucky no one said, "git gud" yet.
Control the center with pawns and pieces, normally develop knights before bishops, don't develop the queen early. In the middlegame make plans, whether it is to get a piece to a certain square or checkmate.