This is something that first time new home builders can get hung up or confused on.
There are 4 main items we recommend completing before talking to a builder:
Having purchased our $295 plans
Having a site plan
Having stamped structurally engineered plans & load calculations required by your municipality in order to obtain your building permit.
Too many think that they immediately need to start talking to a builder. In our experience this isn't the case. It's much better to prepare as much of the pre-construction work as possible so that when it comes time to build, you're more likely to land a credible builder and very few questions will remain.