Setup VPN in Digital Ocean for Private Access to Servers

I have few servers in cloud for which I want to enable access only via a seperate VPN Server. I will enable private network access to all servers from VPN server. 1. Setup OpenVPN (Not the licensed version) in Digital Ocean Server 2. Share simple commands on how to add other servers to the VPN setup 3. User Management - Can provide simple command list to add/remove users 4. Configuration to enable/disable public internet when user is connected to VPN 5. Configuration to enable/disable user traffic to go through VPN alone.