First set up a new VPN Server on the controller:
[Sitename] --> Settings -> VPN --> Create New VPN Policy
Purpose: Client-to-Site VPN
VPN Type: VPN Server - L2TP
IPsec Encryption: Encrypted
Authentication Mode: Local (Or LDAP if you managed to set it up)
Local Network Type: Network
Local Networks: <chose the networks for access>
Pre-Shared Key: <chose a password to use for VPN>
WAN: <select yout WAN interface>
IP Pool Type/IP Pool: <Set up the IP ranges. Use existing networks otherwise there will be no routing>
Next, set up a user in the tap VPN User.
VPN Type: L2TP/PPTP
VPN Server: Select the one you just created
Mode: Client