If a repository is created using SkeltaList as a resource provider, then by default a sample user (User Name: admin, PWD: admin)will be created in the SkeUsers table. You can use these credentials to login into the  site & design/Execute a workflow. You can even create more users once you login into the EC site. There is a "users" TAB which by selecting, you can find the option to create new users with all the required properties. All the newly created user information will be stored in the SkEUsers table. Then you can use these users in the workflow to assign Tasks/Execute workflows.

Hope i answered your query.

Thanks,

Mallikarjun