The installation deploys the families inside the folder: Documents.
The families for Revit 2015 are:
1) fmStair01-15 – On the Left hand side.
2) fmStair02-15 – On the Right hand side.
For Revit 2016 the prefix of the name is the same but the suffix 15 to 16 changes.
Of course the user is free to move the families into the folder that he prefers.
It is very important that during the drawing operations the user doesn’t change any content inside a family; for that reason it may be useful to create a backup copy of the families.