The simple way is to enable sync in the Classic catalog. If you imported raw files into LRCC on your iPad, they should have automatically uploaded to the Adobe cloud, so if you're signed in to the same Adobe ID on your Mac then as soon as you enable sync all images stored in your cloud space will download into the Classic catalog (full originals). Before you enable sync, checkout the Lightroom Sync tab of your Classic Preferences menu, where you have options to change the default local location for storing the downloaded images, and if you use a standard date-based folder scheme in Classic you can set the downloads to be placed into the same structure.