Start with the legs. Each pair of legs are notched in a manner that helps you match them.

A drop of glue will affix the proper set of legs together. Next, add a base to the model.

Match up two torso halves, spread some glue along the seam, and press them together.

Pop the torso onto the legs. Think about how you'll want to pose the arms before you commit.

Add a pair of arms from the sprue. There are plenty to choose from!

Clip off a pair of shoulder pads and glue them in place on the Possessed Marine.

Add and pose the model's head.

Line up and glue the backpack in place.

Now, add extra bits or spikes from the sprue. In this case, yet another set of mandibles!

Now you have an assembled Possessed. The sprue allows for many poses, so experiment!