The RM-70 is the Czech version of the BM-21 multiple rocket launcher. It is mounted on a Tatra 813 truck chassis with an armoured cabin. An advantage of the RM-70 over the BM-21 is that it can carry a second pack of rockets. These can be loaded automatically, allowing it to shoot two salvoes in quick succession. The RM-70 was introduced in 1971 and seved with a number of armies in the Warsaw pact and all over the world.

Wikipedia has more information about the original.

Luke Ueda-Sarson has a web-page about modelling the Czechoslovak army. The chapter about artillery has an example of a finished model.
Micro Armour Mayhem, Arctic Strike and Guild Wargamers also have pictures of finished models.

This item consists of 4 models on a sprue. The launch tubes and a bulldozer blade are separate items on the sprue.
To mount the dozer blade, the towing hitch (coupling) on the front fender must be removed. To mount the shovel, cut the shovel and D-shaped sprue from the main sprue and glue it under the cab, right back to the chassis rod - see the 3D sketch.
The launch tubes can be mounted pointed in any direction. two sets of tubes are mounted at high angle, two to shoot at low angle, which is also the position used when travelling.