I was sent Five STP files and all but one were as parts. the other one came through as a surface import.

when i run import diagnostics it tells me i have one gap, heal gap does not work and if i try to close gap there is only one line.

I need this file as a part so any help would be greatly appreciated.

I'm not the most adavanced on solidworks so if you do know how to resolve this then the simpler things are explained the better, thanks.