Hi Pegii
Looking at that schematic kind of looks like two coat hangers connected to make a large wire loop. So start with that first. Then measure the circumference of the wire loop. Write that down. Next you will need a roll of magnet wire. The AWG of the magnet wire is not specified. So you will have to choose first. I happen to have a large roll of 20 AWG magnet wire. That measures .032" in thickness. But different size magnet wire has different thicknesses. Anyway all you need to do to find out how many turns of wire to use is to divide the circumference of the wire loop by the thickness of the magnet wire. So if the circumference is 60", then divide 60 by .032. That comes out to 1875 turns. I might choose thicker wire though, to cut down on the number of turns.
Here is a schematic of a converter circuit you could use with capacitor and resistor values shown.