can't import apx file to hairworks viewer

Hello,

i cant load the apx hair asset to viewer, it give me "file open error"no matter what i tried it never solves it,i’ve already searched everywhere but all say to make sure the mesh is skinned with at least one bone, and so is my mesh so i cant figure how to solve this

also whats growth mesh ? i ddnt understand why in tutorial two meshes were used for the project! i need help =(