Questions re a new pool and advice sought

[daisy22]

Having just become new above ground pool owners, I just have a few questions to ask in order to keep my pool clear, clean and safe.

1. How many chlorine tablets should I use, the ones I have are 5g?
2. How often should I use them? i.e. daily, every 3 days etc.
3. My pool measurements are 24ft x 12ft x 4ft - how can I calculate how many litres of water it holds?
4. Dependant upon the litres, how often should I use the pump and for how long?

Any other advice is welcomed with thanks

I should have added before that I have tested and the DPD/pH are ok, after the water was a little bit green a few days ago.

Also, as I am in Europe I can't work with gallons, so if anyone can help with metric measurements even better