To remove the side panels:
Loosen two slotted-head captive screws near the panel base.
Tilt the panel bottom out.
Lift the panel up until free of the tabs at the top of the chassis.
To replace the side panels:
Place the panel against the cabinet so the notches on the panel inside align with tabs at the chassis top.
Lower the panel into place and allow it to hang flush against the chassis.
Tighten the two captive screws at the panel base.