Use Salesforce Connect to link an External Object with Salesforce Users

The mobile phones being tracked by an external application are used by specific users in your Salesforce instance. Create an indirect lookup relationship between the 'Phone' External Object and the 'User' standard object.

• Create an OData 2.0 external data source with 'Mobile Devices' as the label, 'Mobile_Devices' as the name, and this URL: https://phone-odata-demo.herokuapp.com/devices.svc/. Note: If you have completed the previous challenge in this module ('Setting up Salesforce Connect'), the External Data Source should already exist in your Developer Edition.
• Add a new 'Phone UUID' custom field on the User standard object with the resulting API name of 'Phone_UUID__c'. The field should be of type 'Text' and marked as 'Unique' and 'External ID'.
• Change the 'UUID' field on the 'Phone__x' external object to be an indirect lookup relationship to the 'User' standard object. Use the 'Phone_UUID__c' field as the matching key for this indirect lookup relationship.
• Update any existing User record in your Developer Edition instance to have a value of '0000123442' for the 'Phone_UUID__c' field.

Challenge not yet complete... here's what's wrong:
The User standard object does not have a custom field with the API name 'Phone_UUID__c'

Anybody could help me to pass this one, please? I am not sure what User standard object is supposed to be, as I can not see any. Unless, this challenge was/should be updated.