Have had many users find it difficult to figure out how to run a log in manager or even stop auto login once installed. Decided to add lxdm log in manager. Live iso still logs in automatically. If you wish your user to have password login edit of /etc/lxdm/lxdm.conf.
Then comment it out:
At some point I will edit abinstall to do this for user, so you will have to log in using your users password.