As Dave8671 said, start by looking at the TV fool report for your location, this is required to determine which channels you can expect to get what kind of antenna you need
- UHF only, VHF-Hi +UHF
- Directional, bidirectional or omni-directional.
Then you can either buy or build an antenna
(assuming your TV has a built-in tuner than can handle OTA signals, it should if it was built in the last 10 years or so but I'm not sure what you meant by 'Nothing at the back of the tv')
If you intend to build one stay away from youtube videos most designs found there are flawed.
One good resource to get started is the digital home OTA forum: https
/www.digitalhome.ca/forum/186-antenna-research-development/
Personally I like my m4, there is drawings available on that site : https
/m4antenna.eastmasonvilleweather.com/
Other than that gray-hooverman antennas also seem quite popular : http
/clients.teksavvy.com/~nickm/
If you want something simple that doesn't require too much material just for a quick test look at the Stealthhawk antenna on the same site as the gray-hooverman, I just mentionned, it's simple to build, personally I was not getting a good enough reception on all the channels I want with it (I can only use antennas indoors which is not ideal....), but it's much simpler to build than the other 2 variants I mentioned so it might be worth a try.