The whole rig could be brought into action in about 2-3 min. by lowering and locking the rear stabilizing pads, and lowering the front blast shields into place.
Loading of the racks took from seven to ten minutes using the usual crew of five to seven men.

Elevation was limited to a maximum of 45 degrees.
Traverse was either 10 or 20 degrees according to the chassis used.
The sight used was a MP41 dial sight normally used for mortars.

The control box was located in the cab, towards the right under the dashboard.
The ignition sys­tem was electrical and the battery and generator were in bins just behind the cab.
Wires ran up to the rails and connected to two contact strips about .75m forward of the rail's end inside the grooves.
The two contact strips passed the current to two contact points on the upper end of the rocket chamber which triggered a detonator in the upper portion of the fuel charge.
The cab control consisted of a rota­ry switch box, and the entire sixteen round load could be salvoed by a quick snap of the wrist.

The rockets re­leased at .5 second intervals to pre­vent them from striking each other in case of slewing, and therefore the whole load was fired in eight to ten seconds.
While it was possible to fire the rockets individually, such as for ranging, this was not a common practice.
The fuel burn of an M-13 rocket lasted .7 to 1.0 second.

Source : S.Zaloga, »Soviet Rocket Artillery«.

Note : The order of rocket ignition is pure speculation, any further information is welcome.