Hey guys i'm trying to add a tapered hole from a curved surface to a flat surface. (I'm extremely new and this is the first thing I've ever drawn on solidworks)

I drew a miniture snowboard so i can use it as a handle on a jewlery box and as a finishing touch, i'm planning on extruding a threaded circle for the screw to insert to.

It's a bit hard to describe what i did but here's a picture of the issue im having.

I want to get rid of the part that's stick up above the board itself, but i'm not sure how to do so.

Also could someone also teach how to make a threaded hole? I've been doing this entire project based on youtube but it's proving to be more time consuming than i thought and would like

Thank you!