Concerning private and public servers. How do you connect to your private server after you have created NAT Gateway, assuming that you did not copy your private key into you public server. Thanks. Please what are the steps
A pvt instance can only be accessed either by a VPN connection or another instance in the same VPC (using the default local route).
DMZ/Bastion- You dont necessarily need DMZ – it is just a specific use case of access.
NAT Gtwy has nothing to do with inbound (or even pvt) access – it is only for outbound.
Pvt Key (used only for key based access – recommended approach) – your key should be installed in the target (pvt) server.
There are other advanced scenarios – peering connection, pvt interface etc.