What is it?
On the side or top of your screen (depending if you play blockheads portrait or landscape), you will see a little box with your character inside it. It will show a heart (health) and a smiley face (happiness).
If you click on it, you can see your details about your health, happiness, hunger, energy, and environment. You can also sleep (when you are tired), and meditate to skip time. Also, you can purchase a workbench for 50 time crystals.