To configure a default printer to use with Express 1 and / or to set up a default label location, go to the Shipping menu in Shiplark and click on Configure Shipping Providers. Then click on the shipping provider, for which you want to configure settings. The same settings can also be accessed by going to "File >> Configure store >> Shipping", and then clicking on the relevant shipping provider.
To set the default shipping options for express go to "Shipping >> Configure Shipping Providers >>Express 1". Once you are there you can set the printer defaults as required and then click on "Configure Default Shipping Rule" to access the default settings.
Remember to click on 'Save' to save your settings, once you are done with the configuration.
Reference: Express 1 settings, printer settings, ecc express one settings.