I have a form called 'drawings' and I want to have some fields where users add notes about the drawings. These notes are 'operations'

The problem I have is each drawing will have different operations, some only 2 operations, others maybe 12. Each operations will have a run time too, so 10mins for operation 1 and maybe 30 mins for operations 2 (for example)

What is the best why to deal with this?

I hope I have explained it well enough, I am new to zoho but so far it's bloody amazing so far. Just need a but of help on my way. 

Thank you in advance