Thank you for confirming.
You really need the proper remote to access the necessary functions.
You can TRY using the side panel buttons, but you likely won't be able to fully navigate the menu.
First, you need the input mode set to TV (not hdmi, etc).
Then press the MENU button to get to menu, and you'll then use the channel and volume buttons to move through the menu.
Get to the Initial Setup section of the menu, and then you'll see channels. Make sure the mode is on air/antenna (not cable) and then you can find the auto scan (channel scan/program) function from there.
If you can't get there with those buttons, your only option will be to buy a replacement remote: http://amzn.to/1ShRc32
The remote is under $10 online, and you're better off having it anyway as you'd need that remote to change channels and volume anyway (without having to get up and walk to the tv each time).