How to build a real analog Theremin that produces sine waves instead of digital square waves?

Can someone please help me with the design of a fully analog Theremin (producing sine waves instead of digital square waves) using coils that can be bought easily or made easily out of parts that are commonly available? There are many Theremin schematics available online but I can't find one with clear & detailed explanations of how to wind the coils or make the antennas or where to get the parts. Please understand that I am not an electronics expert. Any help would be greatly apprectiated.