Without all the gobbly **bleep** jargon, there's no difference. Hook up the antenna and "scan for channels". Choose antenna, not cable, and the tuner in the Roku TV will find all the OTA (over the air) broadcast channels your antenna can pick up. However, if you choose to "display streaming channels" in the Roku settings menu, then the Antenna Channels you just scanned for might not show up - this is what's been happening to a lot of users.
It's funny that my other 2 Smart TV's that are NOT Roku, do not have this problem and list the streaming channels after the complete listing of OTA channels. No switcheroos or problems displaying either type together.