If you are lost and it is dark in the wilderness you should first understand your immediate surroundings. Take a look around and try not to wander far off as you want to avoid getting injured if it is dark. Look for large trees, rocks and other natural formations that you can use to start building your primitive survival shelter.
Keep it simple:
Remember you want to build a primitive survival shelter which basically means you need a small space covered that you can fit in to for protection from the weather. The most basic design of using a few tree branches leaning against a large tree trunk or rock can provide a basic frame.
Find proper location:
Find the proper location to build your primitive survival shelter. You will need to look for large trees, a hilly outcrop or some rocks and boulders. You basically need to use these large natural items as the base for your primitive survival shelter. Once you have found a spot then start to clear away the brush or grass to make some room for yourself.
Now look around for some decent sized tree branches. It does not matter what shape they are in as you will need to drag them to your base location. The more wooden branches that you can find the better your primitive survival shelter will be. Do not worry about the size of the wooden tree branches as you can always lean the smaller ones up against large branches to fill in the gaps.
Lean wood against base:
Take the largest branch that you have found and lean it at an angle against the tree or rocks that you have chosen for a base for your primitive survival shelter. Keep placing more branches to make a sort of angled roof. Once completed make sure you have enough space to either sit or sleep under these branches. Also, make sure that the branches are angled properly and are sitting against the tree or rocks properly as you do not want them to slip down and fall on you.