Try this link: http://www.nmra.org/beginner . The web site in for the NMRA - i.e. Nattional Model Railroad Association. It has good and basic information for the beginner about starting out a layout.
The NMRA web site has lots of information so be sure to follow that link and check it out. As to your questions, the answers depend on what you are doing. HO, N, S, and O all offer different options for automatic turnouts and the choice of elctrical system (DC or DCC) also makes a difference. After you read the NMRA stuff, come back here and give us some specifics about what you are doing or want to do and you’ll get lots of ideas. Welcome to the hobby.