LayOut has two systems to prevent lost work: file backup, and auto-save.
File backup works like this: every time a file is saved, the previous version of the file is renamed with a "~" (on mac) or with "backup_" (on windows). This file will be in the same directory as the actual file that you're working on. If you ever save a file, and then realize that you saved changes you didn't want, you can try opening this backup file to basically go back to the last saved version.
Auto-save works like this: when LayOut crashes, it leaves files behind in the user's temporary directory. The next time LayOut runs, it presents these temporary files in the "Recovered Files" dialog. Since this happens automatically, it's a bit harder to know exactly what state your work is in.
So, to recover work, the first thing to do is to look for the backup file. If that's not present, or is too old to be useful, you can run LayOut and see what's available in the "Recovered Files" dialog.
thanks,
Marc