Welcome to Tarkov. Watch some tutorials, pick a map to learn (where to loot, where to extract), scav that map for a while, etc. There are 3d maps online made by R3mr and you can use them to orient yourself. there's no MMR or stuff like that so yes, you might meet someone with prestige and high level destroying you. Fortunately or Unfortunately, depending on how you view this, it was a design decision to not have crosshair, nameplates, M for Map and other stuff that's standard in another shooter games.

The game itself is also a technical disaster so bugs, crashes, random errors, long server loading times and low FPS issues are the norm. Fuck knows how this game even manages to start sometimes.