README: add simple example song

README.md

@@ -11,6 +11,33 @@ one gate (digital) output.
 Each track has an associated octave value, by default 4, in which it will
 play note values.
 
+### Example
+
+```text
+channel 0
+bpm 120
+legato on
+octave 2
+
+play c
+play d
+play e
+off
+
+play c
+play d
+play e
+off
+
+play c
+play d
+play e
+off
+
+play b
+off
+```
+
 ### Values
 
 - Note values, either **simple** like `C`, `A#`, and `Db`,
@@ -40,7 +67,7 @@ This value can be given in `c`ents, `s`emitones (which is the default),
 - `play <note>` (abbr. `n`) sets the CV value to a given value and turns on and off the digital output for one beat minus the trigger amount (or simply leaves it on if legato is configured).
 
 - `wait <time>` (abbr. `w`) makes the program wait until the next value.
-Without the use of wait, all changes are executed simultaneously and
+Without the use of wait or play, all changes are executed simultaneously and
 the output will simply be the last values set on the channel.
 
 - `off` (abbr. `o`) turns off the digital channel.
@@ -52,6 +79,8 @@ very short time, then turns it off.
 
 ### Channel Control
 
+- `channel <int>` sets the channel currently being controlled.
+
 - `octave <int>` sets the octave, between 0 and 8, to which simple and relative note values will be played.
 
 - `bpm <natural>` sets the tempo of the channel. This is the time used by the time value `beat` and by the `play` instruction.