what should i do in endgame?


I don't understand the 1900 and 2000+ part. Are you trying to say that's a goal of yours?
As for being 1000 rated and wanting to improve at the endgame, a lot of being nervous comes from lack of playing experience. Once you play many king and pawn endgames, you'll have a better understanding at how to convert them successfully and this will make you less nervous. You'll just trust that your position is good and play on. Here's some videos of mine you may benefit from checking out:

Which videos?
They are shown in the post above. If you are on chess.com mobile, then videos or pgn game diagrams may not display like on PC. View on a computer, or search my YouTube channel yourself. The videos are titled:
- How To Win With ONE Pawn! Chess Endgame
- Learning The Chess Endgame Concept of Backwardness
Both on my KeSetoKaiba YouTube channel: https://www.youtube.com/@kesetokaiba/videos
As for me, I dont do anything to improve, I have been moving pieces randomly 20+ years and dont bother
> what should i do in endgame?
you should try to promote your pawns and to checkmate your opponent, or to move your lonely king back and forth to "win" on time, or just switch to YouTube while your time is running out...
Follow these principles, this is pretty much everything I know about endgames
1. Pawn structure in the endgame - be mindful of having pawn structure weaknesses, avoid multiple pawn islands, isolated pawns, doubled pawns, backward pawns
2. Double Minor piece endgames - Bishop pair is almost always to be preferred to a knight pair or a knight and a bishop (there are exceptions like direct attacks against the king, the knights may be better depending on the circumstances)
3. Single Minor piece endgames
- Bishop is better than the knight when pawns are on the two sides of the board, the knight is better than the bishop when pawns are only on one side of the board (a lot will depend on king position distance from pawns etc so again there are exceptions)
-Opposite colour bishops favour the attacker but in most cases have drawish tendancies. So if you are a pawn or two down go for a pure opposite colour bishop endgames with no other pieces.
-Knights are bad against outside passed pawns Bishops are not
-Keep a bishop of the colour of the queening square of the opponents passed pawn
4. Rook endgames - Stay active, double on open files, sacrifice pawns for rook activity
5. Rook and Queen - Stay active, focus on tactics
6. King and pawn - Stay active, centralise the king

There are many types of endgames that can arise, so here are some that apply to all:
- make sure your king can be an active piece. This means that in the endgame the king can go around taking stuff in the middle of the board, and its time for him to leave his castle.
- ultimately, your goal should be to queen a pawn.
These are the main two principles.

At 1000, watch Daniel Naroditsky's endgame videos. He has a play list explaining the basic concepts and he explains it nicely. Here's the link: https://youtube.com/playlist?list=PLT1F2nOxLHOfQI_hFiDnnWj4lb5KsviJ_&si=HgX_404o3rHTiHh9

Hi,
I am rated over 2400 online (https://www.chess.com/member/ppandachess). I created a free course that will teach you a training plan to improve, including how to play in the endgame. Feel free to check it out: https://www.panda-chess.com/daily-improvement-plan
I think that my free training plan can help you.
I also offer private lessons: https://www.panda-chess.com/private-coaching