To build a gate in Tribes of Midgard, you will need to gather wood boards, cut stone, wrought iron, and 600 souls.
When you gathered all four resources, you will need to place all of the resources at one of the three gate locations in your village; doing so will then build a gate that can be used to keep hordes out and in place.
But if you don't have any of these resources, you can get them by gathering basic materials using both a lumber axe and pick.
Starting with wood boards, you will need to chop down the various trees in the game and take them to the Tinker NPC, but you will also need to upgrade here to level three before you can make wood boards.
To do this, you will need souls, and you can get them fast by clearing camps and killing enemies and Jotuns in the game. Farm souls and you will be able to upgrade the Tinker NPC and make all of the required resources you need, such as wrought iron.
But before you can make wrought iron, you will need to gather up ore and iron from iron deposits that you can find in most regions in the game. The same goes for cut stone. You will need to gather stone and flint from flint deposits and stone from stone deposits to make cut stone.
Do all of this, and you will be able to build gates among other things in your village, such as archer towers. You can also build worksites, which we highly recommend doing as they can slowly build up the number of certain resources you have over time.
Check out some more Tribes of Midgard guides at Pro Game Guides!