First, install Raspbian.
Install the Cisco IPsec VPN server (https://github.com/hwdsl2/setup-ipsec-vpn) using the command below.
$ wget https://git.io/vpnsetup -O vpnsetup.sh && sudo sh vpnsetup.sh
Set up new VPN clients. https://github.com/hwdsl2/setup-ipsec-vpn/blob/master/docs/manage-users.md
typo.. VNP clients -> VPN clients (last line)