There are defined legal rules about this - it is known as 'laying off' staff.
Start by reading here about the statutory rules:
https://www.gov.uk/lay-offs-short-timeworking/overview
There are then follow up pages on the Government website that explain guaranteed pay elements as the result of lay-offs.
I won't repeat here what is given at this website, but ask questions again for more help.
Doew your employment contract say anything about lay-offs? - if not the statutory position applies.