Well, it's fairly simple as far as gameplay goes. Throughout the map there's trees, rock boulders, hostile and harmless wildlife.
Destroying boulders results in a drop of iron ore, copper ore, silver ore or rocks to drop.
Cutting down trees results in two pieces of lumber being dropped.
Killing wildlife results in their corpse being available for looting, which generally contains meat, bone and skin.
You then construct buildings, tools and whatever you may need to survive using these resources. All resources are items and can only be carried by heroes.
You need to keep check of your food though. So you need to make sure that you're farming or hunting. You can fish too, if you have fishing boats.
While doing this, you'll use some of the resources to upgrade technology to enable yourself to hire stronger troops and to boost the power of your hero as well.
Also, you need to build walls, towers and hire troops to defend your growing empire. That's about it for a general description.