With default Ubuntu configuration you just have to enable/install OpenVPN server (1) (server), generate one user certificate (2) (server) and configure NetworkManager profile (3) (client).
All the other steps are just intro to using Linux and/or Amazon EC2 infrastructure or such technicalities as copying files or (unnecessary) configuring time zone.
All the other steps are just intro to using Linux and/or Amazon EC2 infrastructure or such technicalities as copying files or (unnecessary) configuring time zone.