All Printed Circuit Board Design is done on Mentor Graphics Pads Layout software.
To get started all that is required is some form of schematic. Whether it be a jpeg, pdf, or a scanned napkin you jotted down some idea on.
From there I get started. I use the latest tools to generate an intelligent schematic that is not only pictorally accurate but contains connectivity information (also known as a netlist) and component details that can be uploaded to the layout tool . The schematic can also output a spreadsheet (bill of materials) that contains manufacturer and vendor part numbers with descriptions and pricing.
I will next send you a copy of the schematic for your approval.
To start the layout I will need the board shape and dimensions either verbally or attached sketch. Then I'll complete a parts placement and send you a copy for review before starting the routing of connections.
From there I will send you copies of the completed board for review before generating gerber files for the fab house to make the boards.