Ironically, I've linked to the very page I was looking for.
This page about Arcstaff, lists some combinations.
Combos
In the following sections, R1 = Light Attack and R2 = Heavy
Attack (on PC, these are bound by default to LMB and RMB,
respectively). Light Attacks consume a small chunk of super energy
while Heavy Attacks consume a larger chunk of super energy.
R1: Basic attack.
R2: Unleash a destructive wave of energy that travels along the ground.
R1, R2: Basic attack followed by an uppercut.
R1, R1, R1: Basic combo with light conal damage.
R1, R1, R2:
Basic combo with a heavy conal finisher.
R2 while airborne: Heavy
downward smash. Radial area-of-effect damage centered on the point of
impact.