Which model do you have? In general, first make sure that the source is set to TV. Look for a Source or Input button on the TV. On some models, the buttons will be on the back of the TV. On others, the control panel buttons are on the side or under the front bezel. Now, try the Menu button and use the Up/Down arrows to go to the Channel icon. Press the Menu button again. Then use the arrow keys to make sure that the TV is set for Cable or Over-the-Air as needed. Press Enter to change this using the Left/Right arrows. Press the Down arrow to get to the Auto-Scan option and press Menu to launch the scan. Often, the Channel Up/Down arrows are the equivalent of the Up/Down arrows on the remote. The Volume +/- buttons are function as the Left/Right arrows.
These directions apply to the Polaroid 19GSR3000; the manual for this is available here: http://polaroidhdtv.com/wp-content/uploads/2013/11/UM_19GSR3000.pdf
. You can find other manuals for some Polaroid TV models using the drop-down menus here: https://polaroid.com/support
. The Polaroid manuals for TVs from 2014 and later are here: http://polaroidhdtv.com/support/#tab-id-2
I hope this helps.