How to Expot a .FBX from Unreal with Rigging, Textures and BlendShapes?

I obtained a 3D model in the UE4 Marketplace which is very customizable (Arms size, legs size, body fat an etc) and wanted to export to see how this was done behind the scenes. I mean, how the 3D model was prepared fror this (probably Blend Shapes).
But, when exporting from Unreal I could only get a mesh without texture/materials and with a broken rigging.

Could you help me?

Sorry if it is a duplicated one, by researching in the AnswerHub I could only find some unaswered questions about this topic or some simple solution of the Asset Action > Export which results in obtaining only the mesh with the rigging without BlendShape information and textures

Thanks in advance!