Read the Printify catalog: which garments exist, who can print each one, and which sizes and colours that provider offers. Saves the three ids every product needs.
The steps
POD — pick a blueprint, provider and variants runs blueprints → providers → variants → margin → save.
Who can run it
POD — pick a blueprint, provider and variants reaches an instance's own resources, so it runs on an operator's Leumas Studio; open it here to read and adapt it.