Hi Nika Ulianova,
1. You will take it from the start of the new tax year- 06/04/22.
2. You can use the exchange rates from:
Exchange rates from HMRC in CSV and XML format
3. If you are claiming the remittance basis, it will be the money you take and the money you spend on your card
Remittance basis 2022 (HS264)
4. You need to complete SA100, SA103, SA109 and SA106.