The link above has good information on doing mud set showers
I have a very old tub and I like to replace with a floor tiled shower .please give me instruction how,
30/70 says that even with the instructions you will do something incorrectly. A built in shower is not a good first time project.
A shower is not rocket science...hundreds of people have done some awsome work for the first time with the guidance on www.johnbridge.com.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014