Heart rate zones - how many % for eacg zone?

Hello.

I'd like to ask you for advice/help.

1. When you set your heart rate zones how many procent % do you set for each zone?
2. Do you use LTHR or resting heart rate as a base and what's the difference between them when setting zones?
3. Why are there different zones for running, biking etc?

Thanks for your help and suggestions
:)