Loading a save file will remove all chests and coins from the map that you have already opened/collected. It does not yet support removing enemy spawn points, hero items, or shop items. Because of this, it is suggested that you only have the 'Chests' and/or the 'Coins' layers activated when you load a save.
You load a save file by clicking the 'Choose File' button in the bottom-left corner of the map.
If you click here, the standard Windows savefile location will be placed on your clipboard. You can then paste this into the file selection dialog and press 'enter' to automatically bring you to your save folder.