Most 4k TVs and HD TVs these days have built-in digital tuners, so you probably don’t need a DTV converter box (see below for more info). You just plug-in your antenna using a coaxial cable into the back of your TV and start scanning for channels. Your TV might ask you to automatically scan, or you may need to go into the settings and choose auto or manual scan for channels. Keep in mind, the input on the TV must be set to antenna or TV (most TVs have multiple input sources such as HDMI1, HDMI2, USB, etc). Once the input is selected, your TV should ask you to automatically scan for channels.
Last, download the necessary software. You can download a compatible app for your Mac right from myhdhomerun.com. You can also download the HDHomerun app for iPhone and iPad. On Apple TV, you can use Plex with your Plex Pass subscription or Emby with an Emby Premier subscription, or you could also side load Kodi and use the HDHomeRun add-on. If you don't already use Plex, Emby, or Kodi on your Apple TV, you should probably get Channels for Apple TV (my personal recommendation) or InstaTV Pro.
You can likely also get a lower rate (a promotional rate) by starting a new cable contract. Although no one likes being tied to a contract, it does reduce your bill. And you may not need to be a new customer to get a new contract: Try calling your cable company and asking about a reduced rate in exchange for a single-year contract. This arrangement carries the risk of paying a penalty if you need to get out of the contract early, but if you’re planning to be in the same place and to keep the same cable/Internet service for the next year, it can save you a good bit of money.