By plugging the proper cable(s) from the cable box to your TV.
Be warned, COBY was never a quality brand, and they went out of business entirely several years ago. I'm actually surprised your TV is still working. It probably doesn't even have a HDMI port, so it may really be in your best interest to just go buy a new TV -- and please don't waste your money on another crappy brand. Stick with the big names - Samsung, LG, Sony, Panasonic or Philips. If you really must save money, look at Vizio, or at worst, TCL. Everything else is junk.