1. Use axe to chop down two normal-sized trees, and strip them of branches.
2. Chop down 25 small, young trees, only a few centimeters thick. Strip them of branches as well.
3. Tie one of the small trees in a horizontal shape using tied together tall grass/leaves, forming a shape similar to that of a staple.
4. Use the other small tree trunks to form a grid of sorts in a diagonal line on one side, one end near the top of one of the large tree trunks to the ground, to provide structural support. Each square formed by this grid should be 1 foot squared. Add smaller vertical trunks along this line as well, with a singular small diagonal trunk along the vertical trunks.
5. Weave branches w/ leaves between the squares, for insulation from the outside. It will have enough leaf branches once it blocks all sunlight.
6. Add leaf branches on the sides, either by tying them with more grass-cord or by stuffing them through the diagonal branches.
7. Add MOAR LEAVES for the shelter floor, to make it more comfortable.
In the end, should look somewhat like this: