How do I unclog a bathtub drain

https://www.hometalk.com/diy/repair/plumbing/how-to-unclog-a-bathtub-drain-the-easy-way-2208156

Cover up the overflow with a wadded towel, and plunge away! If that doesn’t work, you c try baking soda and white vinegar.....give it ample time to work, and then follow with boiling water. Last resort......go to Hime Depot or Lowe’s and buy “Liquid Heat”, a drain cleaner. If none of these methods do any good, you may need a plumber to snake out your drain.

Think cathy covered every thing i was going to suggest. Once cleared baking soda and vinegar down the drains every week or two to keep them clear

First things first, it is most likely clogged up with hair and soap gunk. Get the little plastic thin strips with the barbs that are made for taking out the hair. Use it until you get no more hair. Then put down half cup of baking soda and a cup of vinegar, let it work for about fifteen minutes or until it quits fizzing. Put down about a gallon of boiling water to wash all of it away. Do not use a plunger if you suspect there is a hair clog, it might put it down to far to grab and then you will need to snake it out. Good luck, this should help clear it out.

Bathtub drains are usually just junked up with hair. Can you remove the drain screen? Usually it's held in place by a single screw.

If so remove the screen and clean it off. Now you're going to create a poor mans drain snake. Grab a coat hanger (or something similar) and straighten it out, bend a hook on the end of it and use that to fish out any hair that is caught down in the drain.

Hope that helps!