Overview
If you have multiple sites under a Site Collection and want to manage access per site or across the entire collection, it’s best to create custom roles. This gives you flexibility, for example, some editors can be Authors for the whole Site Collection, while others only have access to a specific Site.
If you only have one site or don’t need granular access, you can use the default Site Collection roles and Site roles in Sitecore. In that case, simply run the Setup Security script on your Site Collection and then on the Site.

Recommended Role Structure
Create custom roles before running Setup Security.
Preferably create 4 roles per Site Collection and 4 per Site. Use the Sitecore domain.
Site Collection Roles:
sitecore/MySiteCollection Admin
sitecore/MySiteCollection Author
sitecore/MySiteCollection Designer
sitecore/MySiteCollection Member
Site Roles:
sitecore/MySite Admin
sitecore/MySite Admin
sitecore/MySite Admin
sitecore/MySite Admin
Create your new custom roles for a new Site by creating 4 new roles.
Create new roles in the Sitecore domain. Follow this pattern:

For the headless Site Collection, you create 4 new roles for that Site Collection aswell.
Role Membership Setup
In Role Manager, select the <Site> Author role, then click Member Of. Make it a member of:
sitecore\<Site> Member(itself)sitecore\<SiteCollection> Member
You can add additional Sitecore roles (e.g., Sitecore Client Securing) if needed.
Read more about Sitecore roles

Running the Setup Security Script
- In Content Editor, right-click your Site Collection and run Scripts > Setup Security.

2. Choose sitecore as domain

3. In the dialog, link the 4 custom roles to the appropriate fields before clicking Assign.

4. Then repeat for the Site.
You can now assign users to your new Author role and they should be ready for editing your site. Don’t forget to setup Workflows to make the editor experience as expected in Page builder!
Notes
If you only have 1 site or don’t see a reason to split the roles up in any way, there are default Site Collection roles and Site roles predefined in Sitecore that you could use instead and just run the Setup Security script on your Site Collection and Site. But for granular access rights I recommend setting up site specific roles.