What are the basics of PCB design?
PCB design in brief
A schematic is the representation of component symbols and net connections between them. Nets are the traces on the board. Pre-layout is the next phase in the design process where the BOM (bill of materials) from the schematic is verified for long lead time components and obsolete components.
What is PCB layout guidelines?
PCB layout best practices recommend that you always place short, direct traces between components when possible, although this may not always be practical in larger boards. If your component placement forces horizontal trace routing on one side of the board, then always route traces vertically on the opposite side.