Modding Issues (The Witcher 3: Wild Hunt)

In general, I want to change Geralt's model to Leto from Gulet. When I managed to replace Geralt's model with Summer everything worked out, but there was a problem after editing .w2mesh ->. Fbx Summer in Blender. I import this .fbx, change it, then export it back to .fbx, then convert it back to .fbx via Autodesk FBX Converter x64 2013, as there were problems after exporting from Blender, then everything seems to be imported, a mod is created and after entering The The Witcher 3 turns out to be such a disaster.
Before the .fbx change, there was Geralt with Leto's body, everything is as in the picture, only the model was standing as it should, and not hanging in the air.