Hi Blazze,
It's actually somewhere in between. The process begins with a blueprint, which is created by an architect. Once a blue print exists, it can be taken to a build site and the site can be staked out. Once the site is staked out, each of the various "modules" of the house (e.g. each wall piece, each door and door frame, each rooms flooring, etc. -- the "sub-assemblies" of a house) that are called for in the blue print must be manufactured and installed on-site, and in a particular order to build the house. You can't build the room if you haven't laid the foundation, for example. Building a house generally is a process that takes multiple people. (though depending on the house it can be done by a single person, too, at the expense of time, labor, and probably quality)
So, in essence, you start with a blueprint made with architecture, then you stake out a site using surveying, then you build each of the house's components using various trade skills and finally you install each component into the house to assemble and raise the structure.
Hope that helps! :)