A:
In the case of THIS unit (the Toshiba DVR620KU, just to make sure) you need a TV that has a VIDEO OUTPUT: Either composite video (RCA jack), or S-video. You'll also need to make an audio connection (L&R RCA jacks) so you don't get silent movies. If you can make one of these connections, you can record either to recordable DVDs or videocassettes.
If you WANT to get an external tuner, you can connect its audio/video outputs to the DVR620KU, but it has no RF connector, so you can't make a direct antenna connection like an old-style VCR. But you won't need one as long as your TV has its own tuner AND VIDEO OUTPUTS.