I am completely lost and confused on this challenge and I dont know how to fix it. Every time I try to add Edna Frank as an external user it says "An account owner must be associated with a role to enable portal users or transfer portal users to his or her account." Anyone know what I'm doing wrong?

In this challenge, you set up the external sharing model, create a sharing set, and create a customer community user. First, set up the external sharing model with Case set to private. Then, enable Customer Portal settings, and create a sharing set titled Share cases with customers for the Customer Community User Profile. In this sharing set, grant customer community users read and write access to the case object for all cases associated with their account.
Ensure that your DE org user has a role assigned.
Create a customer community user from Edna Frank's contact record. (Your DE org should already have a contact record for Edna Frank. If it doesn't, create a new contact with first name Edna and last name Frank.)
Ensure that the account associated with Edna Frank has cases associated with it.
Ensure that sharing set mapping is set to User:Account = Case:Account.
 

Challenge Question:
Assume a company needs a user whose job is to solely review existing accounts and report on them, but does not require the ability to edit the records. They should only see records from the Account object. Create the correct profile for this user.The profile must be named 'Account Reviewer'.
The 'Account Reviewer' profile should use the 'Salesforce' user license type.
Any user assigned to the 'Account Reviewer' profile should only have read access to the Account object (and no access to any other object in the Org).

I did every thing as tiralhead instructed but i am getting this error.

Challenge not yet complete... here's what's wrong:
The 'Account Reviewer' profile does not work as expected