i have experience with Shopify app development, let me which one api (store front or admin api) you want to use for app development.
By using Shopify api we can get , edit and manage products, orders, users, abandoned cart, collections and some other activities.
On click installation on Shopify it will redirect to our server with details and access token so we get the access token and by this access token we can do all these stuff ( added above ) .
we can discuss in more detail over chat.
i am ready to start now.