Update README.md with instructions

README.md

@@ -6,3 +6,27 @@ EmojiOne v2 Installer
 EmojiOne v2 is an emoji set more comprehensible than Android's one [before Marshmallow](http://blog.emojipedia.org/android-6-0-1-emoji-changelog/).  
 Version 2 of EmojiOne is the last [open and free](https://github.com/Ranks/emojione/blob/2.2.7/LICENSE.md) version of EmojiOne. EmojiOne v3 and later are **not open** to the public anymore.  
 The flashable ZIP saves a copy of the previous installed emoji on your device at `/system/fonts/NotoColorEmoji.ttf.old`.
+
+
+Build
+===
+
+Run the `build-zip.sh` shell script:
+```
+source build-zip.sh
+```
+
+This will generate a `emojione_YYYY-MM-DD.zip` file.
+
+
+Install
+===
+
+You'll need a custom recovery installed on your device, such as [TWRP](https://twrp.me/).
+
+Restart your device into recovery and start `ADB sideload`. Then run:
+```
+adb sideload <flashable-zip-name>
+```
+
+Alternatively, copy the resulting ZIP to your device storage, restart your device into recovery and use the GUI `Install` or `Install ZIP` option.