Check the products and prices the import created. Move any left in Uncategorised to their category, and give each a level and its user groups, as for any product.

Run the PaddleSubs - Resync user groups task (see PaddleSubs - Resync user groups(task)) until it reports that it is done. Imported customers then have the groups their imported access grants.

Look at a few customers in Components → PaddleSubs → Access Subscriptions. Imported ones show Imported as their transaction status; customers see Carried over from our previous system.

Turn off sales on the old system, so nobody buys there after the move.