I have seen several videos where they use ngrock to extend as a local server to other devices, however, I don’t know how, having my app on AWS, I link it with shopify
Hi there 
For Shopify App local development it is common to use tools like ngrok to expose the your local development server to be addressable over the internet. In the Shopify Partner dashboard the Application URL is set to ngrok url.
If you are hosting your application on AWS, and it is accessible over the internet you do not need to use ngrok or another tunnelling service. You will set your application URL in the Partner Dashboard, to the domain of your application.
While this documentation is for Heroku and Fly.io, it may help to understand what is necessary for deploying a Shopify App.