Amazon AWS - EC2 Setup
Most instances must be run inside a VPC. Each VPC has subnets, each subnet is bound to an availablitiy zone.

Make sure the subnet’s IPv4CIDR is set to 10.0.0.0/24.
Back in the main config, make sure there is a security group assigned (VPC instances all must have one).

And make sure to Auto-assign an IP or you can’t login to the instance!
For the security group, edit the Inbound and Outbound rules:

Not really sure what is what or which is which, just make sure they’re all set to Anywhere e.g. 0.0.0.0:0.
To login, you’ll have a *.pem file which you get from creating a key pair name.
ssh -i my-key-pair.pem ubuntu@ec2-198-51-100-1.compute-1.amazonaws.com
DO NOT follow Amazon’s guide when logging into a Ubuntu instance, the default user is ubuntu not ec2-user.