You want the finance office to see money, project managers to see capacity, and everyone else to see the work and nothing more. A permission profile is a list of views that an Owner switches on or off, and gives to people through groups.

Profiles decide which views a person sees. Hiding a view removes that screen, and for the views that hold their own records it also removes their data from search, exports, notifications and the AI. Resources and Financials have three levels, so a person can read the figures or also edit them. A default profile covers everyone, and a profile on a group adds to it.

The full chapter, with every step and setting, is in the app: open your account menu and select User manual.