here is a link for your tv's manual: http://store.vizio.com/documents/downloads/hdtv/VOJ320F1A/171Manual.pdf
1. make sure you have power
a. connect a working device such as a clock, radio, or lamp to the wall receptacle to verify power works at receptacle
b. confirm power cord is firmly inserted into receptacle and to the tv.
c. some appliances have a main power switch in addition to an on/off switch. confirm that if this is the case and make sure the main switch is set to on if applicable.
d. check tv to be sure it is powering on. you should see a power indicator illuminate or you may see the screen illuminate and perhaps display a logo screen when it is turned on. If the set is on, operating volume and channel or other functions should display something on the screen.
2. Make sure a working device is connected to your TV and is powered on.
a.. if the set is powered on, a source must be connected to the set in order to view a picture and hear sound. you should see connectors on the back of the set for various devices and connections. If you have an antenna, connect it to the antennae connector terminal. you will need to acces the settings to do a channel scan or set up to see any channels you might receive.
b..you may have a dvd player or set top box for satellite or cable or an internet streaming device such as a roku to connect. connect the device using the appropriate connectors and cables. once the output of the device is connected to an input on the set, select the input the device is connected to on the set from the tv remote or the side panel buttons and power on the device. hopefully you will see a screen displayed on your tv. if your audio is connected, you should be able to play a video and hear sound. just check all connections to be sure your output connections on your connected devices are attached to the appropriate inputs on your set with the appropriate cables. you may need hdmi, s-video, optical, rca or other cables depending on the device connections and your set connections.
c. if you still can not get a picture or sound, try your device with another set and try other devices on your set such as another dvd player or a camera.
hope this helps.