Download the FortiClient VPN app from the iPhone App Store
Open the Fortinet app and allow all prompts
Click on "Select connection"
Click on "Add Configuration"
Enter "CSHL" for the "Name"
Enter "https://vpn.cshl.edu:443" for the "Server Address"
Enter "443" for the "Port"
Click "Save" in the upper right-hand corner
Once the Configuration has been added, click on "CSHL" for the "User VPN Gateway"
On the VPN screen, select the "Connect" toggle and enter your CSHL credentials and password and connect to the VPN