If you would like to import products inside your Online Store, you will find two ways to address this.
The first one is right after once you create your online store, as the following banner will be the one presented to you with the option to already import your products, as below:
The second method to import your products would be in the Products section, on the top-right corner, as below:
Currently, you are only able to upload product following a CSV feature format. The CSV should not be in very strict format since AI can aggregate a lot of different CSV files and adapt it inside your Online Store 💡