To check the configuration is complete and correct you should run a 'Connection Test'. It is ran automatically when using the web interface when advancing from Source Platform and Destination Platform Settings.
Provided your configuration is complete, the connection tester will launch. If any of the connection tests fail, your migration configuration is not correct and migrations of user accounts will fail.
Check the error messages in the connection tester and adjust your configuration, or set up the migration platforms as appropriately. Pay particular information to the documentation sections for configuring the source and destination platforms.