There is the way it is in Beta 3...
And the way it is SUPPOSED to work.
For now, put beta 3 out of your mind and here's how it is supposed to work:
A player is supposed to start out with a fertile land resource nearby. These rare and special places are where you get your food.
You build your settlement near one of these (at least initially) and build a farm on it.
Later on, you will want to send your pioneers out to find other resources you think your kingdom needs. Maybe you need more food to grow your cities further. Maybe you want armor for better weapons and armor. Maybe you need crystals to get ahold of magical equipment. And maybe it's a shard that increases your magical essence.
If you can't find food, you have one other choice: You can sacrifice 1 essence of your sovereign to imbue the land to have said resource (food, metal, what have you). But doing so, of course, diminishes the potential of the Channeler in question.
So that's the way it's SUPPOSED to work. My job is to get this in before the modding beta lest the modders implement it for me and demonstrate to the world just how lame I am.