Connecting antenna cable and cable from cable company

Hi, I just purchased this TV. It only has one coax antenna input plus other RCA type inputs. I plan to connect it to an external HDTV antenna to receive true HDTV and would also like to connect it to my Charter cable company cable service. I do not want to rent one of their boxes since I get all the cable channels (non-HDTV though) for free thru the basic cable running to every room in my house. How can I connect both coax cables to this HDTV? Thanks. Tom

Just got a 19 inch and the LOCK is on. How do I turn it off?