Need help getting smash bros to work on Dolphin

[Technickal]

I'm a complete beginner at this stuff so please go easy on me. I downloaded everything and I can only get smash bros to work at 25 FPS, I am extracting the .iso to winrar because when I search for it from dolphin it does not show unless it has been extracted to winrar. So I open it up and it lags like crazy, I think my computer is capable, I may just be doing something wrong. Please help!