Here is something to get you started:
Key Eb LH/RH
Practice this first with each hand then put it together:
Bassline (LH): Eb, G, Ab, A, Bb, C, Db, D
Chords (RH): Db-Gb-Bb, C-F-Ab, Bb-Eb-Gb (back & forth)
Gb-Bb-Eb, Ab-C-Eb, Bb-Db-Eb (back & forth)
Oh I'm a
Eb, G / Db-Gb-Bb so-
Ab, A / C-F-Ab
Bb, C / Bb-Eb-Gb dier
Db, D / C-F-Ab in the
Eb, G / Db-Gb-Bb army
Ab, A / C-F-Ab of the
Bb / Db-Gb-Bb Lord
C / C-F-Ab
Bb / Bb-Eb-Gb I'm
A / G-B-Db-Eb a
Ab / Gb-C-Eb soldier, in the
*Ab / Gb-C (optional filler)
*G / F-B (optional filler) in
*Gb / E-Bb (optional filler) the
F / A-C-Eb-Gb ar-
Bb / Ab-C-Eb rrrr-
Eb / G-Bb-Eb my
Bb / Ab-Bb-D-Gb
(repeat)
Basically you running a bass line in you LH and playing occasional chords in your RH. That is about as basic as it gets.