Amazon AWS WebApp with MongoDB

I have built a mobile application that needs to connect to my SpringBoot-WebApp which in turn has a MongoDB and some other things in the background.

I want to deploy this WebApp at Amazon AWS, but I am overwhelmed by all the possibilities. So far, I have just created it as a .jar, and ran it that way, and it worked fine at my other server. Now, for traffic reasons and such, we want to move it to AWS. I have found out, that I need to create a .war instead of a .jar, which is not a problem. I then learned to upload this .war to Elastic Beanstalk. However, my application needs to connect to a MongoDB. I have logged on to AWS via SSH and installed MongoDB there and created the database, but it does not seem like this is the right way to do it.

It'd greatly appreciate if anyone could give me a hint on how to do this as I am very confused.

Thanks and best regards!