Seems that you open foreign cad/neutral file into solidedge.
have you try to open the file into Assembly?
if the original / foreign cad/ neutral file you opened is already converted from assembly to part (previous user).
im sure u can use multybody design to make it solid with view steps.
Has an error opening the file, which type of extension opened? I advise you to open the file again in assembly, if the error persists have to rebuild the open surfaces that can generate a solid which leads to more work, otherwise would be the best design from scratch.