Connect PC and Macintosh computer

Since I know nothing about Macintosh computers I need to know what it takes to connect a Macintosh and PC so that I can share files and printers between the two. I have a HP PC and a Macintosh computer connected to a LINKSYS 4-port router. Both computers can access the Internet, but I need to know what to do on each computer that both computers can talk to one another, basically file and print sharing. Any advice is greatly appreciated.