Authenticating your online account in the MigrateMan application is a 10-second process - simply go to Accounts tab and click add account option and follow the process to authenticate your account.
On accounts tab, you'll see a set of supported services. In order to add an account click on the little '+' icon you see in front of the service name. On the new pop-up window that opens up, click on 'Add New' button.
You will be taken to the login page. Enter your account details and then 'Authorize'.
Once the authorization process is complete and desired accounts are connected, you can begin the migration process.