Plese help me why I can’t install manager on my mac that using os x yosemite?
Did you follow the instructions in this guide
I did but when I wanna drag the manager icon to install, I didn’t fine application folder, why?
Your Applications folder is in the main directory of your hard drive:
It is also accessible in the Finder from the Go menu:
It is probably where every program you ever installed is located. This has nothing to do with Manager. It is a feature of macOS.