To install an Android Widget and Add it to your home screen do as follwos:
1. Go to the Application list
2. On the top right of the screen, select "Widget"
3. Choose the Widget you want to Add to your home screen
4. Tap and Hold on the item to move it to the home screen
5. That's it
Note that this instructions is working for Samsung Galaxy series with Jelly Bean and may not work with other ROMs or Devices