Electronic designs begin with a specification describing what the finished product must achieve. Ideally this is a detailed technical document but some customers have only a rough outline and need guidance before a suitable specification can be created.
Component selection and circuit design are closely related and constant reference to the specification is made throughout. This stage of the process results in a schematic diagram and component library captured on CAD.
PCB layout begins by defining the PCB shape and size together with the positions of critical components such as switches and displays. These can be imported from the customers CAD files if available. The components defined in the circuit schematic and component library are then positioned on the PCB and tracking is added to complete the design.
Files are generated for creating the bare PCB, bills of material for component purchase and for PCB assembly.
These files can be used to obtain quotes from sub-contract manufactures for prototype and volume quantities.
It is usual to order a small number of prototypes for testing and (if the PCB contains a micro-controller) to develop software.
This is the final chance to make changes prior to volume manufacture.
You may take the finished manufacturing data to a sub-contractor of your choice or I can help you select one.