1. Go to 'Administration'-'Drop Down Lists' and click 'Hotel Event'.
2. Click 'New Hotel Event' in top right corner.
3. Add a 'Name' of and select a color (this color will be shown in the grid), you can change 'Opacity' number to make the color lighter or darker (larger number will make it darker) and set the 'From' and 'To' date. 'Save' in top right corner.
4. The event will show in grid like this, on hoover at the date you will see the name of the event. Directly after adding an event you may have to reload the grid page in order for the event to appear in the grid.