First you need to Build the Small House, then finish the Main Hall. For the Architect Achievement you need then to build three wings at your house. You can chose Armory, Kitchen, Library, Alchemy, Storage, Trophy Room or a Greenroom.
For a complete house (Small House + Mail Hall + 3x Wings) you ~ need
158x Quarried Stone
129x Sawn Log
48x Iron Ingot (181x Nails, 16x Hinge, 11x Iron Fittings and 11x Lock)
11x Corundum Ingot (11x Lock)
You can mine Quarried Stone, Sawn Log and Clay around your house. Also your Steward sells that. Sawn Log can be also bought from a Mill. For Corundum and Iron Ingot just visit a Blacksmith, wait 48h and buy again.
Happy Building :D