Laravel API with AWS

I need help in integrate AWS API gateway with luman as end point. I have working project with one web part(Laravel) and three luman project for different micro services. We are using AWS API gateway to point out to luman services. Right now we don't have any authentication on web services on luman. Anyone can have access to these if he know URL. We are planing to use oAuth2 for authentication. but i am not able to understand how it work. As we have mobile app for this project too. So my question is.

Is oAuth need to be implemented on luman project or on AWS API gateway.

In both cases how it will work. Also we are planning to move luman project to private network(no internat) which will not have public access. in that case we need to use lambda function to communicate with the private network. So how it will work in this case.

Please suggest.

via Chebli Mohamed