Shopify’s admin has a built-in bulk importer at Settings → Products → Import that accepts a CSV in its own specific column format. Getting that format right by hand - especially the rules around variant and image rows - is the most common way a bulk import goes wrong.

Choose the Shopify import CSV format in the extension to build the file correctly automatically from the source store. Upload the result on the Import screen, and Shopify will show a preview before committing anything.

Because the extension marks every imported product as an unpublished draft, you get a safety net: review titles, prices and images in the admin, fix anything that needs it, and publish only when you’re ready.

It’s worth doing a small trial import first, even with a well-formed file - five or ten products, checked over in Shopify’s own preview screen - before running a full catalog through, so any surprise shows up on a handful of products instead of thousands at once.