通过热键启动我的应用程序并从Finder（macOS）传递它的参数

I'm only starting macOS programming. Did some tutorials, reading docs at developers.apple.com. Trying to implement a simple(?) thing, but can't seem to get the whole picture for now. I want to be able to launch my app by pressing some hot keys combination. The app itself is just a window with a text field that has a list of selected files in Finder (if any). Naturally, I'm not asking for a concrete implementation. But some hints and directions on the general structure, or on what concepts and classes to inspect would be very helpful. macOS 10.13.4, Xcode 9.3.1, Swift 4I'm only starting macOS programming. Did some t