there are a lot of way to make a shelter. but here we have one that it´s very easy.
Find a suitable place to build. Generally, the best place to build a shelter is in a "fringe", an area between an open field and dense brush zone. Having water near is important, however the shelter should be built no less than 50 meters away or the water vapor might cause unwanted cooling of the area or flood unexpectedly.
Search for an object to brace the shelter against. Long boulders or fallen trees can be ideal for bracing a shelter, but any large, immobile object can work. It is also possible to tie a long branch between two other branches braced in the ground, though this can be more difficult and slightly less sturdy. Some people prefer to brace a sturdy, forked branch in the ground and lay a longer branch over the top. There are many different possible ways to build a lean-to.
Find sticks to lean against the horizontal brace. These sticks should be somewhat sturdy, as they will form a side of the shelter. Be sure that there is enough room between them and the brace for you to crawl inside comfortably.
Pile small branches and twigs over the stout sticks. Leave only the two ends open. These sticks will form the other side of the lean-to shelter.
Pile small debris such as leaves, grass, and moss over the frame. These will provide further insulation and protection from the elements. Nearly any small forest debris will work, so long as it won't blow away readily.