Which climbing harness should I choose as a beginner?

Your first climbing harness

As a beginner, comfort is the most important thing. You will sit in the harness a lot and you will therefore want a well padded hip harness with well padded leg loops. As a beginner, make sure you buy a harness with a fixed size and not a "one-size" harness, as it easily becomes an annoyance with long loose hanging straps.