Players can build houses and other things in this game. Just turn on your build tab by hitting the Customize button and turning it on.
Each tile you build cost resources.
When you are done building your house you should upgrade it by getting next to it and right clicking it. This also takes resources. Upgrading it will make it harder for people to bust your walls. They will need more BP to destroy the walls. The more knowledge you have the higher you can upgrade them. See the Science section for info about gaining knowledge.
Upgrading 1 tile upgrades all current tiles built by the same person as the tile you upgraded.