If you put the presets (whose filenames end in .lrtemplate) in the old preset folder location (prior to 7.3), then when LR 7.3 or later starts, it will automatically convert them to the new format (.xmp) and folder location. See this article for the old and new folder locations: https://www.lightroomqueen.com/lightroom-classic-file-locations/
Thanks John. But I don't know where the old location was. I have a new computer and don't have LR 3 anymore. I just have a zip file of the presets. Am I SOL?
Unzip the presets. Then follow the instructions from that article:
To find them easily on either platform, go to Edit menu (Windows) / Lightroom menu (Mac) > Preferences > Presets tab and press the Show Lightroom Presets Folder button.
Each type of preset has its own subfolder, for example, Filename Templates and Metadata Presets.
If you have older style .lrtemplate Develop presets, place them in the Develop Presets subfolder and restart Lightroom. They’ll be converted to .xmp format and copied to the shared Camera Raw Settings folder.