Building Units and Buildings

In order to upgrade buildings, and to construct new buildings and certain kinds of units, such as Artillery and ships, you will need to produce Hammers, which represent work being done. Hammers are made from Lumber, so you need to produce lumber, either by cutting down forests, or by placing a colonist on a forested tile next to your colony and ordering him to work as a lumberjack (right click on the unit to give it orders). Then you can place a colonist in the Carpenter's House in order to convert the lumber to Hammers.

Units and advanced buildings also require Tools, which are made from Ore. So you need to place an ore miner on a tile that produces ore (Hills, for example) and another in the Blacksmith's House, in order to convert the ore into tools.