To avoid corrupting your save... Never change load order or remove mods mid-play-through. You can only safely upgrade a mod, or add mods to the end of your load order.
The rule is in general, not just for Toys mods. Breaking this rule is the #1 cause for a wide range of problems. Save cleaning tools help but won't remove all corruption.
The so-called "clean save" procedure (myth) breaks this rule... instead, start a new game when unable to follow the rule (a new game means really a new game, not some early save).
For more Golden Rule detail, see this FAQ.
Most common problems (aka. fails to install Toys mods)
Breaking the golden rule (above). This is by far, #1, and includes failing to start a new game if using Toys for the first time
Forgetting to build with Bodyslide, including each time you update the related mod... Building toys in Bodyslide
Forgetting to build FNIS, and watch for and fix any errors, including each time you update
Missing a requirement... for example, for SE, did you forget MFGFix or Racemenu? Or wrong version of a SKSE based utility mod?... see SE versus AE Version Trap
Go through each step in Requirements & Installation on the main download page, and make sure you did not miss anything else
Forgetting to run the Toys MCM Installation Test
The test saves you time, instead of finding out later, that something was installed wrong. If it fails, don't expect Toys or Toys Content mods to work. Yes, the test "doing nothing" is a fail. If it fails, use steps to fix if the test in MCM failed.