Add installation instructions on MacOS readme

README.md

@@ -53,7 +53,63 @@ TODO
 
 ### <a name="install-macos"></a>MacOS
 
-TODO
+The easiest way to install espanso on macOS using the [Homebrew](https://brew.sh/)
+package manager, but you can also do it manually.
+
+#### Using Homebrew
+
+The first thing to do is to add the official espanso *tap* to Homebrew with
+the following command:
+
+```
+brew tap federico-terzi/espanso
+```
+
+Then you can install espanso with:
+
+```
+brew install espanso
+```
+
+To make sure that espanso was correctly installed, you can open a terminal and type:
+
+```
+espanso --version
+```
+
+At this point, you have to [Enable Accessibility](#enabling-accessibility) to use espanso.
+
+#### Enabling Accessibility
+
+Because espanso uses the macOS [Accessibility API](https://developer.apple.com/library/archive/documentation/Accessibility/Conceptual/AccessibilityMacOSX/)
+to work, you need to authorize it using the following procedure:
+
+Open a terminal and type the command:
+
+```
+espanso install
+```
+
+A dialog should show up, click on "Open System Preferences", as shown here:
+
+![Accessibility Prompt](images/accessibility-prompt.png)
+
+Then, in the "Privacy" panel click on the Lock icon (1) to enable edits and 
+then check "espanso" (2), as shown in the picture:
+
+![Accessibility Settings](images/accessibility-macos-enable.png)
+
+Now open the terminal again and type:
+
+```
+espanso install
+```
+
+If everything goes well, you should see the espanso icon appear in the status bar:
+
+![macOS status bar icon](images/espanso-icon-macos-statusbar.png)
+
+If you now type `:espanso` in any text field, you should see "Hi there!" appear! 
 
 ## FAQ