Need help converting 2D drawing to Rhino8 3D

I’m not sure which application you are using.
You post in the iRhino category - iRhino is a viewer only and won’t let you change your geometry.
I haven’t heard of Rhino8 before.

If you are using Rhino 5, you should be able to use RemapCPlane to put your side view geometry to the right viewport, and front geometry to the front viewport.