Microsoft Project on the Web (Project Plan 1) . Here: Definition Workdays

Hi There. We are currently looking at the Microsoft "Project on the Web" solution. Where can it be entered there that saturdays are a regular working day for a specific person? Unfortunately we couldn't find anything. thnx for helping.

Vid with the problem you can see here: https://immarketingforum-my.sharepoint.com/:v:/g/personal/marcuz_hello-world_net/ESmCdIIys6hMldZfJUzj9AQBLXq33-G-1Hur6c2KmqwHqA?e=6hYHpf