The whole command post is internally large enough to accommodate 4-5 figures or a single large 50-60mm base for an MMG or a light AT gun.
In the following you find some details on the construction of the command post, and some comments on things i would not redo in the same way... I hope you like it (as my germans do) !
Here is an overview of the construction of the command post. I cut a 10x8 cm rectangle from mdf and drilled 4 holes where i put the 4 wooden pillars. the two in the back are 1 cm taller than the front ones. The pillars are glued to the base with hot glue.
Then I cut the wooden horizontal supports for the sandbags (about 2.5cm tall) from a 1mm thick balsa wood sheet. I carved 5mm spaced horizontal lines on the balsa and hot glued it to the pillars.
On top of the pillars i put iron nail heads and hot glued them since i wanted to magnetize the roof to make it removable... At the end the effect is nice but magnets tend to unglue easily from the balsa wood. In addition when the roof is removed the model remains with the 4 exposed pillars and is not nice... A better overall idea could be to glue the pillars to the roof and do not glue them to the base... even without magnet it should look fine and it gives you a usable trench without roof...
The roof is made by a 2mm thick balsa wood with carved lines to simulate wood boards. Note the glued magnets.
I did the sandbags with DAS making little sausages and then squeezing and cutting to 1.5 cm long bags. DAS should be kept wet while modeling and to have the various lines of sandbags sticking to each other.
Finally I made the muddy terrain with plaster mixed with ochre pigment, sand and vinyl glue where I put some boards of balsa wood.
Here are some pictures of the finished model painted with GW paints.