[Help] MyHack not working?

I'm trying to install Mavericks on an old computer and the guide for my specific model says to use MyHack, so I want to do that just to minimize my chances of messing up.
The only problem is that it wont let me do anything, there's no clickable options.

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I used this program in the past and I don't remember having any problems, the menu for creating a USB installer came up instantly, but this time nothing happens. Also the download page says the program hasn't been updated since 2013, so I doubt it's a bug because it's not a beta or anything like that. What should I do?
I'm trying to run this on a real Mac on Mojave 10.14.1, if that helps.