how to install osm map on ubuntu 20.04

It would be best if you follow one tutorial (I recommend https://switch2osm.org/serving-tiles/manually-building-a-tile-server-20-04-lts/ ) and than ask with the specific errors you get.

Nonetheless I would not recommend to install a planet osm map on a vps, esp. not the one you seem to be using (you may try that for testing, but than you should got with a smaller extract, but those specs - which in case of the one you are using are better "on paper" than in real - won't get you anywhere for productive use for a full planet install).

What would also help would be to explain what your end goal is - you say you want to "install osm on a vps", but presumably you're doing that because you want to do something with the data?

Maybe that something is "create a tile server that could be used instead of https://tile.openstreetmap.org/ " in which case the "switch2osm" guide that @Spiekerooger linked to makes sense, but there are many other ways of accessing and using OSM data (for routing directions, for example).

It would really help to know what you are trying to achieve.

i want to use Osrm and Nominatim basically running everything i dont want somebody to limit my requests i wanna use it for commercial use

so which server should i use ???

OK, you're going to need to follow the installation guide for each of those projects, and I'd do them one at a time so as not to become confused.

For Nominatim, the instructions seem to be https://nominatim.org/release-docs/latest/appendix/Install-on-Ubuntu-20/ .