This is the first time I'm firing up Octamed to actually do something 
First tried Protracker only to find out it did not support input from midi keyboards. (I tried the version 4 beta)
Using Octamed I'm not even sure if I've set up the sound properly because some midi files I try from the CD actually don't produce sound when I play them.
There are a number of things you need to do / check to play your keyboard and record it into OSS.
Title Menu
MIDI -> Active ------------------------------check yes
MIDI -> Input Active ------------------------check yes
MIDI -> Input Channel (is 01 by default should be fine)
MIDI -> Read key ups -> --------------------check yes (optional)
Connect stuff correctly (to play into OSS):
Keyboard (MIDI OUT) ----> Amiga (MIDI IN)
You probably want a block set up with at least 8 tracks.
"Main Control" window, Check off yes to Chord .
In the main tracker window "S" button means selected. When you play the keyboard, your **** will be recorded on to those tracks.
If you do not want stuff to be recorded on to a particular tracks, be sure to un-select those.
Oh, did I mention you need to have edit mode clicked on? You do (ESC key).
1. edit mode on
2. play your block ( start it looping )
3. play your keyboard
4. watch the magic happen
5. stop and play back the magic