How do I find a track in an earlier version?

I'm finally on Logic X and I am totally confused about project management. There seems to be a very different workflow. For 25 years I have worked in Pro Tools and Logic and its early versions. Typically after making a big change to a project I make a "save As" that I can easily retrieve if I want to go back, and there are auto backups. Last night I seemed to have lost a track. How do I find the track in an earlier version? What would be the workflow now to get back to earlier "saved as" and auto backups?