Fire

 

We have been using fire for thousands of years. Fire is our source of food, comfort and heat. That's why it's really important to be able to build a fire correctly.
First thing you need to know, you don't want to burn down the forest.
I suggest you make a circle with rocks. Don't make it small, you will need a big fire during the night. (1m diameter if possible.) If there are no rocks, you can simply remove all leaves and burning objects around. Make your fire near a big rock so that the heat bounces off from it. 
Before building the fire itself, gather wood for the whole night. The amount of wood should be at least the equivalent of a 5-6m tree. Don't cut down trees, green wood isn't good for fires. Pines burn down fast, if you want to use them, you must gather 3 times the amount. 
Then, gather your ignition wood. These are small, dry branches that catch on fire easily. The the ground is wet, use tree bark or pine branches; they will burn even when wet.
Place your wood as it's shown on the picture below, to for a little house. 

 

 In the middle of the structure, place the driest and smallest wood you have.  If you can stuff it with tree bark, do it. 

Light the little structure from the bottom, protecting the flame from the wind. 

Make sure there is always SOMEONE watching the fire. If you are to sleep, take turns to be sure the fire is always on. 

I have been asked if it's possible to light a fire on snow. Yes it his, here is a video (in Russian) that I filmed in the Tarmigan Reserve.