The variation swatches are based on product attributes with images.
1. You need to create a new image product attribute or convert an existing one.
For example, you can go to Products -> Attributes and edit the existing Color attribute:
2. Change the attribute’s type to image and press the “Update” button to save changes:
3. Go back to Products -> Attributes and press Confiture terms:
4. At this point you may already see the images added to the attribute terms:
If not – find and add some images to existing or newly created terms.
Then just use this attribute in product variations.
Follow this link to enter documentation page.