I don’t own the full game just got warzone downloaded
Well shyt in that case, you're going to have to learn by Camping. You don't have the skills to Rush, it's just going to get you killed. Camping is how a large number of newbies get their first handles, every time a new Map drops that's what 1/2 the lobby does until they get the Map down.
In BR, choose Solos. Why? If you're not running with people who are willing to be patient with you, they're going to leave you stranded and/or Quit on you, leaving you facing constant 1 on 2/3/4 situations. No bueno since you're already struggling.
Find an LMG. Why? Good Damage & lots of ammo since you're going to need plenty of chances to hit your targets until you get the hang of it. Find Claymores or Proximity Mines. Why? They're ideal for trapping/holding down a position by guarding Entrances and Exits, which lets you watch your back.
Pick a building in the near center of the Circle, preferably one with 2 floors. Place your Claymores/Mines near the stairs, pick a spot far enough from them that you don't take damage but you keep a line of sight on the Exit. Kill anyone who comes up.
As you get used to different weapons kick, reloading speed, and Damage output, you'll find a favorite(s) and eventually you'll be more mobile & engage people outside in the open. Or you might be one of those people who become lifelong Campers/Snipers.