Only members under the Editor group can edit that portal. Access rights can be given to several groups but edit rights can only be given to a group with a membership type. To assign the Edit permission to a user, you must add him/her to the editors group of the relevant portal.
After entering into the Permission Settings tab, you first need to select the Edit Permission Settings sub-tab to set the Edit permissions on a portal and do the followings:
Click the Select Permission button to open the Permission Selector form.
Select one group in the left pane and one membership type in the right pane. You can select * if you want to assign all available membership types to the selected group.
Click Save to finish your settings.