Problem with surfacing

Hello friends:

I'm trying to do something similar like the attached PH file (this came from a .stl file, not editable) for a university project. I don't have much expertise in SolidWork and  don't know if I'm in the right way, but started with 2 surfaces to then use the knit surface with the option of create a solid and merge the entities, but solidworks gave me an error saying the a solid can't be created. Please check my file MO1.

Any recomendations?

Maybe I should start with a 3D Sketch or other way unknown to me?

Somebody can help me with some intructions to do what I want using surfaces.

Thank you all¡¡¡

SolidworksSurfacing