Before you can do this, you need at least 1 other person in your tribe.(make shore they have a level 10 mec. lvl.) 1st, get the house you want from plans, then, once you can start building, go to as many people in your tribe as you want to help, have the socialize bar come up, go to help build, and the name of the type of house that you want help building should show up, if not, then your system is broken, if it does, click X and they will start.