The Visibility Control settings help you control what's shows to requesters and how you can manage permissions.

There are two ways to control permissions through custom roles. First create a role and enable restrictions by group, location and teams.

Select the relevant groups and locations for the role to access on the Portal.

The second way is to select the base role of a 'Requester' that way default permissions will apply:

[[Next in the visibility control settings select ‘Item Filters’ . These speed up the checkout process for requesters.  Default filters on the Portal include item availability, show available items, location and group filters. Any custom filters can be added from settings ]]

Visibility Control in Request Portal