Client Address Spaces is the client network assigned to the user's virtual adapter when they connect to the VPN.
The authorization in a point-to-site VPN is certificate-based. It is an asymmetric encryption algorithm that is used to sign the communication, where the keys are contained in certificates. A self-signed public key certificate means that the trust to the certificate is given by the fact that it was received by the VPN via an upload from an Azure account by the owner of the Azure subscription.
To create a self-signed certificate for a Windows developer with Visual Studio 2015, Makecert.exe is the tool necessary to generate it. In the Developer Command Prompt for Visual Studio 2015, type the following command:
makecert -sky exchange -r -n "CN...