You can start accepting payments via the Barion Smart Gateway as soon as your Barion Shop is approved.
You'll be informed in a customer center remark about your fees, and the automated withdrawal delay setting, if applicable.
Note that you'll need your shop's Secret Key (POSKey) to request payments in your shop, on the Shops>Actions>Details screen.
Note also that you can create multiple shops using the same Barion Wallet.