For every tile your house will occupy, you'll need 1 carpentry skill. Also, for every wall you'll have you'll need 1 carpentry skill. So if you want to build a 1x1 house (the smallest house possible), you'll need 5 carpentry (4 walls, and 1 tile). To plan the house, go to your flattened piece of land, activate your mallet and right-click a tile, and select 'Plan building'. You can plan additional (adjacent) tiles in the same way; selecting 'Plan building' on a planned tile will remove it from the plan. When you're satisfied with your building shape, right click on it and select 'Finalize building'.
(to be able to plan more than 1 house, you either have to wait for server reset, 24 hours, or finish the first floor walls of the current plan)
== Building the house ==