In one sentence, describe what the following article is about:

If you are located near a river, lake, or other body of water, you can gather mud from its banks. Otherwise, you may need to make your own mud by digging up clay-rich soil and adding water to it. The clay should be a thin consistency so that it will mix well with dry grass. A clay-rich mud or soil will result in a strong, durable cement. Walk to a nearby field or riverbank and pull up a large armload of old, dead grass. You’ll use this to mix with the mud. Green grass will not work. The grass needs to be dry and hard in order to make suitable survival cement. The grass that you’ve harvested will probably be very long, which will prevent it from mixing well with the cement. Solve this problem by using a field knife to cut the grass down into a suitable length. It will be most convenient if you do this on top of a large tarp. For most projects, the grass will work best when cut into sections between 6 inches (15 cm) and 12 inches (30 cm). Do this near the location where you’ve set the cut grass stalks. Once the mud is on the tarp, set about half of the grass on top of the mud. Either wearing shoes that you don’t mind getting muddy, or barefoot, step up and down on top of the mud and grass mixture until the two elements have been fully smashed together. If you don’t want to get your shoes or feet dirty, fold a corner of the tarp on top of the mud and grass and stomp on top of that. At this point, the mud and grass will be smashed into a flat layer. Pick up one edge of the tarp, and lift until the mud/grass mixture folds back over itself. Do this a couple of times, until the mixture is roughly in a round shape. Place the remaining half of the dry grass stalks on top of the mud and grass mixture. Walk in place on top of the mixture, using the same technique as before. This will force all of the newly-added grass to fully blend with the mud/grass mixture, leaving you with well-blended survival cement.  At this point, your survival cement is finished. Begin shaping and working with it immediately, as the mud will dry quickly. You can form your batch of survival cement into a series of bricks, which can be built into a small hut in adverse survival conditions. In non-survival situations, you could use these cement bricks to build a retaining wall or fire pit.

Summary:
Gather thick, clay-rich mud. Gather an armload of dry grass. Cut the grass to a usable length. Pour the mud out on the tarp. Stomp the mud and grass together. Roll the mud and grass back on itself. Add the rest of the grass and stomp again.