Choose some products that you think will be of interest to your customers –  ideally find a dropshipping provider that will send from his own stock (no need to invest in a stock) to your clients directly to their home address – they dont have to carry anything in their suitcase !

Use dropshipping companies  to determine your cost, choose some standard options (material and size for instance) 

Create a product in Stripe (you can have declinations) –  decide of your margin

Include the Stipe product link in the shop from your app client panel, include a photo and a short description there too.

Activate your shop if not already done.

When customers orders  from you in Stripe, go back to the provider, and order from him with a delivery to the address provided by customer. If your provider is well chosen, your have nothing else to do, keep the difference in price.