Ray Wenderlich has a nice basic tutorial around creating a simple menu bar application. I just used it for my own application and it seems well up-to-date. I thought it was this one: https://www.raywenderlich.com/450-menus-and-popovers-in-menu...

A global hotkey is not something I have experience with but it seems that there's a library called Hotkey: https://stackoverflow.com/questions/47760135/global-keyboard...