Cut out a bunch of different shaped bases from hardboard or any other material you have at hand. Bevel the edges with a hobby knife and some sandpaper.

Using insulation foam, carve out shapes that match the bases you have cut out. There is no need to be completely exact, just get it close enough! Shave these shapes into small mounds.

Adhere the insulation foam to the base using a strong glue like Liquid Nails or wood glue. Once they are glued to the base, close the gap between the foam and hardboard base using filler or straight globs of wood glue.

Dig through your bits box and find old sprues of miniatures. Arrange equipment to look damaged and destroyed, and position models into death poses on the mound. Once you have a few models piled up, texture the base.

After basing the whole piece Chaos Black, it was painted. When painting the models on the mound, be sure to add plenty of gore and pools of blood on the ground. Make a few of these and you'll be ready to place them all on the game table to recreate the horrors of war!