I am looking to model a men's style signet ring or find a simple model of this ring so I can put a design on the face of the ring.

I found this model on grabcad: Men's Signet Ring - Lightwave, OBJ, Other - 3D CAD model - GrabCAD

which is exactly what I'm looking for.

That model is an OBJ file, SW cannot directly import OBJ, correct?

I was hoping to be able to get that file and then convert it to a solid or import it as features. I want to have a ring that I can change the size of for different ring sizes (configurations)

I found this tutorial for SW for power surfacing which my version of SW currently does not have. Power Surfacing -威力曲面設計 Signet Ring Tutorials - YouTube

For making this model from scratch, I'm looking for advice on how to create it. My initial idea is to create a series of lofts with a circular guide curve in the center and then just do a cut extrude on the top face to create a flat face.