Setting up merchandising for a new brand

We are looking for someone that can help us setup our ecommerce store for apparel and other merch. Someone that has experience with companies that create the product and fulfill orders like integrating printful.com. Our goal is to come up with designs and push out different merch around the designs. It will be a tourism website and we want to focus on creating merch for destinations. Some merch will just be our brand and others will be destination specific and incorporate our brand.

Please be specific about companies that you have knowledge about and how to integrate our e-commerce site with their fulfillment operations.