What determines what a staff can and cannot do in BRP is roles, and the rights of that role. These can be found in Configuration (green module) > Staff and resources > Roles.
Follow the steps below to edit the rights of a specific role:
Click on the role you want to edit
Click on the pen in the right corner under "Rights"
In the new window you can add or remove rights for this role. To add rights to this role, move it to the right column by marking it and using the arrow button. To remove rights, move it to the left column.
Read more about roles and its rights here.