In Homer, you can use Tags to organize and arrange your information. You can use more than one tag to further categorize and and filter your information. You do not need to use tags if you don't want to.
Some examples of how you can use tags:
Kitchen is tagged with Room. If you open Room, you will see all other spaces that are tagged with Room.
A Dishwasher can be found in the Kitchen. It is also an Item, more specifically a Major Appliance. If you want, you can add or remove tags so that it makes sense to you.
Your Power Drill is normally in the Garage, it is a Power Tool and your friend has just borrowed it, so you also tag it with your own tag called On Loan. It will then be shown with all other things you have borrowed to friends that have that same tag.
When a tag is added, it means that it You can also use tags if you have created an event on the Timeline. You can then couple / connect that event with something specific.
You create a timeline event called "Repainted Kitchen". You can then connect this event to pictures, bills and other relevant information by tagging it with Kitchen.
The warranty for your new car expires in 11 months. You add "Warranty ends" as an event in the timeline, and add the tag Car (or whatever title you have added to your car)