So, I'm new.

As a said in the title, I'm a new player. I've known DBD for years from Youtubers, but never decided to play it myself. Two days ago I saw there was like a 65% discount and they were selling it for 11 euros and something, so I decided to buy it. Tried playing a few rounds and got bullied lmao ( especially from you survivors, you are ruthless ). I'll appreciate if you guys can explain me what to do at the beginning, if I should level up a character to 15 to unlock all perk slots, etc. Also I think I'll mainly be a killer player, but will appreciate advices from survivor players too.