In this example i will use the [BR-DISK](/Radarr/Radarr-collection-of-custom-formats/#br-disk){:target="_blank" rel="noopener noreferrer"} Custom Format the one most people don't want to download anyway and if you do then you probably don't use Radarr or Plex being both don't support it.
Visit the [Collection of Custom Formats](/Radarr/Radarr-collection-of-custom-formats/){:target="_blank" rel="noopener noreferrer"} and from the Table select [BR-DISK](/Radarr/Radarr-collection-of-custom-formats/#br-disk){:target="_blank" rel="noopener noreferrer"}
In the empty `Custom Format JSON` box (1) you just paste the `JSON` what you got from the [Custom Format Collection](/Radarr/Radarr-collection-of-custom-formats/){:target="_blank" rel="noopener noreferrer"} followed by the `Import` button (2).
Personally I would only add the Custom Formats that do what you actually prefer especially in the beginning, including the [Releases you should avoid](/Radarr/Radarr-setup-custom-formats/#releases-you-should-avoid)
Check out the [How to setup Custom Formats](/Radarr/Radarr-setup-custom-formats/) where I will try to explain how to make the most use of custom formats and show some personal examples that I'm using. That you can use to get a idea how to setup yours.