Gary:
I use the 30 amp 12V DC that Ted shows. With the three outputs connected you have 10 amps per output. I have these outputs connected to three banks of Atlas O SPST connector boxes that will go out to various lights. The 12VDC will run LED's and incandescent bulbs.
For powered accessories you will have to set up an accessory transformer. I have three of the old Lionel 1 amp acc transformers (don't think they are made anymore) I use for this purpose.
I use the terminal board Richie shows to distribute power but have started getting into European style terminal strips. I like ferrule crimp connects which work great with the European terminal strips. https://ogrforum.ogaugerr.com/topic/ferrules
Joe