Programming the attiny with arduino

I have been trying to program an attiny chip based on the instructions on the MIT high low tech thing. the problem is, when I download the core files for the attiny 45 and 85, I can never get them to load onto the IDE. I put them in the folder that the preference menu says my sketchbook is in (which would be documents), but whenever I restart the IDE, the core files do not load. I have tried saving the file in different folders, but nothing works. What could be the problem, and how could I fix it? Thank you.

Bot13985 years ago
Did you create the hardware folder in the sketchbook folder.Please recheck I doubt that you created it somewhere else.
Higgs Boson (author)  Bot13985 years ago
I saved in the same folder that the preference menu said my sketchbook was, but it wasn't the same screen as what is shown in randofo's instructable, because it was on windows. The folders and stuff may be configured differently, but I doubt it.
Jayefuu5 years ago
Did you read this too?

https://www.instructables.com/id/Program-an-ATtiny-with-Arduino/step5/ATtiny-core-files/
Higgs Boson (author)  Jayefuu5 years ago
Yes. I did what both places said, and the IDE still won't load the files. I'm using a computer with windows seven on it. would it be worth it to get the ide on an older mac that I have to do this (the macs operating system is just new enough to work with arduino). Would this work better on macs?