So I am trying to do what this article (https://yoast.com/change-wordpress-permalink-structure/) talks about to change my default URL strings from
however I can't for the life of me find the pemalink menu in multisite. I looked in the settings of both the main site and the network admin section. I googled and googled to find a multisite specific location but only really complicated things came up not the simple location of that setting.
Please help me out and tell me how to make this change for the main site and all sub sites.