Select 'Allow' to choose all the access settings you want the custom role to have access to
Select 'Deny' to choose all the access settings you don't want the custom role to have access to
At the bottom, select which users you want to have this custom role
Select 'Submit'
Editing a custom role
In the custom role section, you'll be able to update any custom role by selecting 'Update'. Once you've made your changes, make sure you select 'Submit' to save them.
You can also delete any custom roles if no one is assigned to them. Select 'Delete' and then confirm you want to do it. You can't get this back, so make sure it's definitely what you want to do.