You can always import CSV files manually, with or without a connected POS. POS sync uses the same normalization and matching rules as CSV import.
Square
Items, inventory, orders (read-only) — per location
Connected
Merchant: Velora Demo Store
Main Store
Last synced: Today at 2:10 PM
Auto-sync: nightly
Shopify
Products, inventory, orders (read-only) — per location
Available
Lightspeed (X-series)
Products, inventory, sales (read-only) — per outlet
Available
Clover
Items, inventory, and orders (read-only)
Available