Buy new car battery and buy it yourself

Hello, happy new year all of you. Hope you’ve all been well over the night With us yesterday it was noon time. Car packed, go to McDonalds to have breakfast at 13 o’clock :s and go….nix started. Car didn’t jump any more. Unfortunately battery empty said ADAC, charging current etc. but probably everything is there and the battery “guest” probably already…whatever that may be. After starting aid we are off to Berlin and celebrated. We were there around 6 o’clock. Today at 5 o’clock we are off again. Sprang on. Now definitely a new one has to come. Can you recommend one, which fits and can I install myself? Crafty I trust some to respect but professionals who say that there are things that you should not do yourself. LG