Utilizing The Make A Hole Tool

I set out to create a circular hole in a polygonal plane. I had originally attempted this by creating a plane and then a curve circle on top of it. After realizing that both had to be polygonal i decided to try using a cone and reducing it down to the circular base. After using Mesh>Combine i attempt to select the two faces circular and rectangular plane.

When I attempt to select Mesh>Make a Hole Tool it gives me the warning that two polygonal objects are needed.
Advice? What am I doing wrong?

there error message tells you the answer.. this function works on selections of faces not objects.. so you select the face of the object you want to cut the hole in and the face that is the shape of the hole you want

So you are telling me that by combining the plane and the con that the bottom of the cone does not become a face of the polygon? i have tried and had difficulty trying to cut a perfectly circular hole in just by placing vertex. do you have a better tool for the job?

by the way thank you for the quick feedback

this image leads me to believe that there are two faces on this one polygonal plane.

you could probably get away with using booleans to do this

thank you very much problem solved