When you start a new custom luxury home project, you can hire your architect and builder in many different ways. You can first hire the builder and then hire the architect. You can use the reverse approach too wherein you first hire the architect and then go about the choosing the builder. You can choose the custom home builder and the architect from the same company. For example, if you hire Merlin for your custom home project in Las Vegas, you will get a full team of builders, designers, architects and other professionals who will take care of your project from the start to the end.
There is no correct or incorrect way to do this. But, it is always recommended that you choose them in such a way that they are able to collaborate and work on the project together. I have seen projects where the architect works separately and the builder works separately. They would hardly meet. Such projects can experience many delays and mistakes. This can also lead to unplanned expenditure and can spike your overall budget.