From StrategyWiki, the free strategy guide and walkthrough wiki

This is just general stuff you should know when you start playing.

[edit] The Main Menu

This is where you go to change your equipment, look at the monsters list and do various other things.

[edit] Save Rooms

These look like rooms with large, creepily beating hearts in them, and you press 'up' to get the 'do you want to save' option to come up.