Shopify non – embedded apps

I want to make Shopify non – embedded apps, I have installed the pre-built code which Shopify provides to build an embedded app. In the server.js file, after the user installs our app, it gets the access Token successfully. In order to make an API request to graphql server, it requires the access token to the headers. I am struggling with this point, I don’t know how to get that access token from the backend and make API calls on the frontend, I want to use Apollo Client to show query data on the frontend, but I don’t know how to use that accessToken after the merchants install the app, it has generated it in the server.js file, which is the backend. Are there any tutorials or docs on what I am trying to achieve.