Nick here from Shopify.
To add products to your store you would need to do this from your store admin:
You can also see this in the helpful guide Shopify has that @Vikas_Chovatiya shared here. Once you have added your product to your store here, it is then up to you to decide where to show them on your public store, in term of on the homepage, in a collection or what have you. You can see how to structure your store via the theme editor.
I hope this helps and answers your question. Let me know if you have any others!
All the best, Nick