The Owner user must log in to the portal.

In the top-right menu, select the account by clicking on the downward arrow, and then click on "Account Management" and choose "User Management."

In the new window, you will find the users managed by your portal.

To edit the permissions of a user, locate the user and click on the pencil icon on the right to assign permissions.

Once you have finished configuring the permissions, save the changes, and the new permissions will be granted to the user who needs them.