To answer my own question:

In the manual under Setting permissions on the Store Admin Menu:

A. Setting permissions on the Store Admin Menu
Smith Cart leverages the built in role capabilities of DNN to grant users access to one or more buttons on the store admin menu.
The following DNN Roles are built in to Smith Cart to control button level permissions on the store admin menu:

(The list is in the documentation)

By default all DNN Host and Administrators level accounts have access to all the buttons on the store admin menu. However, in most cases users that are tasked with managing the store will not have DNN Host or Administrator level permissions. Smith Cart supports this scenario by using built in DNN roles that allow you to grant button level permissions to the store admin menu.
Granting Permissions to All Store Admin buttons – SCAdmin Role
1. Navigate to the DNN Admin - > Security Roles menu option
2. Select “Add New Role”
3. Enter the role name “SCAdmin” and click update
4. Navigate to the DNN Admin - > User Roles menu option
5. Assign the “SCAdmin” role to your desired user
6. Go to your BuyNow module settings “Permissions” section

In the permission section of the module settings check the “Edit” checkbox for the SCAdmin role.
Click the update button and the bottom of the screen to save the new permissions. The user that you have designated to manage your store will now have permissions to all buttons on the store admin menu but will not have access to DNN admin functions.