Problem installing milia gem on rails

I can’t install milia gem on rails in my windows. I used to see the instruction, but it didn’t work on my PC. Plz, help. It’s very urgent.

No-one will be able to help if all you tell us is that it doesn't
work. Tell us exactly what problem you have. If posting error
messages then it is best to copy them from the terminal or log and
paste them here. Don't post a screenshot.