“pcb” is software to help you draw (“lay out”) the wires for a custom “printed wire board” (“PCB”).
The recommended way to install pcb is to install the complete gaf package. See installation.
No. “Out-of-the-box”, pcb supports 16 copper layers and …
No.
No.
This is well beyond the scope of this FAQ. There are a few tips at
Generally, you start with a schematic, run gsch2pcb to generate the netlist. See faq-gsch2pcb. Then you might go through the tutorial gsch2pcb_tutorial
Then you … Hey, did you know about the pcb manual, the pcb_tips, and the pcb-quick_reference ?
Yes. pcb_footprints.
There are also some unofficial gEDA footprints at Open Circuits http://opencircuits.com/PCB_Footprints .