Update README.md

Author: itsmeichigo

README.md

@@ -1,4 +1,7 @@
 # Fretboard
+
+![Logo](https://github.com/itsmeichigo/Fretboard/blob/main/logo.png?raw=true)
+
 Lightweight guitar chords in SwiftUI. 
 
 Supports iOS 13 and MacOS 10.15 upwards.
@@ -8,7 +11,7 @@ Supports iOS 13 and MacOS 10.15 upwards.
 
 🌗 Light / Dark modes
 
-🎸 Guitar chords with basic tunings
+🎸 Guitar & ukulele chords with basic tunings
 
 ⏳ More to come
 
@@ -19,5 +22,25 @@ Add https://github.com/itsmeichigo/Fretboard.git as the source and you're good t
 #### Manual install 
 Copy contents from Sources folder to your project.
 
+## Usage
+Get your desired instrument:
+```Swift
+let guitar = Instrument.guitar
+let ukulele = Instrument.ukulele
+```
+
+Each instrument comes with their own name, keys, suffixes and chords. Get a list of positions for a chord using key and suffix:
+```Swift
+let dAug9Positions = guitar.findChordPositions(key: "D", suffix: "aug9")
+let cMajorUkuPositions = Instrument.ukulele.findChordPositions(key: "C", suffix: "major")
+```
+
+Display any chord by sending it to `FretboardView`:
+
+```Swift
+FretboardView(position: dAug9Positions)
+    .frame(width: 100, height: 200)
+```
+
 ## Demo app
 ![screenshot](https://github.com/itsmeichigo/Fretboard/blob/main/screenshot.png?raw=true)