Transition from Windows to Mac OS is pretty hard. It wasn’t easy for me at first considering I’ve been used to using Windows for more than a decade now. Both do have standard keyboard shortcuts but the symbols that Mac uses is kinda different.
The sequence of symbols in a shortcut means that these keys should all be pressed in order to have the desired action be invoked. This does not mean though, that for example a shortcut needs 3 key buttons, you would need to have 3 key buttons pressed at the same time.
You can either press 1 of them first, then the 2nd (while still having the 1st key pressed), then the 3rd. The same way you do with 2 key button shortcuts under Windows. Here is a small guide for you noobs out there.