(*Being 'Completely Alone' entails being away from all sorts of animate and inanimate matter)
1. Stay at home and make sure everyone leaves the house
2. Go to your room and shut the door and windows
3. Sit on your bed and get under your blanket
4. Close your eyes, pinch your nose, fold your ears over their ear holes
By the time you complete Step 4, you will find that you are still not completely alone. Therefore, I'm kindly offering a free Step 5 as a means of supporting you in your quest.
5. Get a new How-to guide.
Good luck.