Automation of VPN connection creation

I’m looking for some help on creating an applescript/debugging for creating an L2TP VPN connection with a preshared key. I have the script creating the connection and filling in the username, and server address. However, I can’t get it to go into Authentication Settings and add in the pre-shared key then apply. Here is the code that I have so far. This is the link that i’ve been working off of (https://macscripter.net/viewtopic.php?id=37392)

set VPN to “test VPN”
set VPNServer to “testvpn.com
set VPNUser to “test”
tell application “System Preferences”
reveal pane “Network”
activate
tell application “System Events”
tell process “System Preferences”
tell window 1
click button “Add Service”
tell sheet 1
click pop up button 1
click menu item “VPN” of menu 1 of pop up button 1
delay 1
click pop up button 2
click menu item “L2TP over IPSec” of menu 1 of pop up button 2
keystroke tab
keystroke VPN
click button “Create”
delay 1
keystroke tab
keystroke tab
keystroke VPNServer
keystroke tab
keystroke VPNServer
keystroke tab
keystroke VPNUser
end tell
end tell
end tell
delay 1
keystroke “w” using {command down}
end tell
end tell