How to remove a bathroom drain stopper

Questions covered in this video:

1. How do I remove a bathtub drain stopper to clean out trapped hair?
2. What tools are needed to remove a bathtub drain stopper?
3. How do I unscrew the cap of the drain stopper?
4. What should I do if the cap is difficult to unscrew?
5. What type of screwdriver is needed to remove the internal screw?
6. How many threads are usually on the internal screw of the drain stopper?
7. How do I clean out the hair trapped under the drain stopper?
8. What are the steps to reassemble the bathtub drain stopper?