The “WordPress Dashboard” option allows you to select WordPress capabilities that will grant access to the dashboard (/wp-admin/).
If you wanted to allow the Author role to access the dashboard you’d add a capability that their role has, but not one that they share with roles below them. In this case, one capability Author’s have that no group below them have is edit_published_posts. Adding that capability to the list would allow authors and anyone with that capability to access the admin dashboard.
Here is an article from WordPress that lists their default roles and the associated permissions.
You could also take advantage of custom roles and capabilities using plugins – this would allow you to create and assign custom capabilities to users which could be used in this setting.
Here’s the documentation article that you can check if you are looking to allow Editor or Author user roles to access /wp-admin/ dashboard.