Hello World, 
I started building my own webpage. The website includes a shop. The shop is now ready and I wanted to try it out. Purchases work fine with the admin account. However, it is not possible to pay / order with any other account. The following error message always appears at the checkout:

403: Prohibited

The Page you are looking for could not be authenticated. die Sie hier suchen konnte nicht authentifiziert werden.

Error message:

Unfortunately, you are not permitted to access documents of the type 'module' (ir.module.module). This operation is allowed for the groups:Settings - (Operation: read, Cashier: 4

Suppose I need to assign rights/ roles to the other users. But where and what rights are these?

Using Odoo 13.0 

Thanks, Chaiks