Screen shots are another technology I'm not good at. Try this--go to this page on arbiter:
https://arbitersports.force.com/offi...Dates-and-Time
Scroll down about half way, to a section entitled Making Blocks "Firm" and Making Notes on Blocks
Essentially, you view the schedule, click on the date you want to firm up, click on the pencil on the left, then the firm box on the right, and then click on the blue disk to save your firm block.