Don't expect any magnetic pulsing device to cure your candida and other chronic infections. Even the inventor did not say it would be used for that purpose.
As a result, all of the following is irrelevant.
However, if someone wanted to make a magnetic pulsing device it could be done.
He does leave out some details, such as how to change the pulsating rate. (I did not read it all) But that would not be difficult to figure out.
The circuit runs on AC. It converts it to DC. A transformer could be used to drop the voltage to an appropriate voltage, and used to power the circuit.
Having said all that, if I wanted to make something like this, I would use a completely different circuit to power it. I am not saying his circuit would not work. I am saying I would do it differently.
You could use an appropriate power supply with a large capacitor across the output, a square wave generator with variable frequency, a solid state relay to switch the electromagnet on and off, and the electromagnetic hand piece.