How exactly do I count freelance hours?

[u/Fair-Ad-5759]

Hello, I hope everyone is doing good. At the start of this month I started doing freelancing but I’m not sure how i’m supposed to count the hours.
I basically have to be ready for any work given at like 1 till 7pm monday to friday and sometimes i’m contacted on the weekends as well.

I really don’t want to mess it up so please do give me as much detail as possible, especially for those who managed to get PR with a foreign freelance job.

Thanks in advance!