Neutron is just one service in OpenStack. You should first have initial idea about the whole components/services and specially basic networking in OpenStack and how it communicates with each other.
Firstly try to install openstack by yourself and start spinning up some VMs. Once you get some hands on the Openstack environment, then you can focus on Neutron component more.
You should go for VPC in AWS before starting Neutron in OpenStack. It will help you to understand the basic things.
To install OpenStack You can follow the given below link.