You are confusing two different things:
Hosted builder - Mac builders maintained by Anywhere Software. No need to run any builder yourself. Just follow the instructions with the hosted builder id.
Local builder - You run the builder on your own local Mac.
A Mac is not required. I just explained the different types of builders as I see that you tried to run the builder on your Windows computer. You don't need to run the builder at all. Just follow the instructions in the mail with the hosted builder id.