In order to use the guest network for an event you will need to have the username and password for the event.

1.  Connect your device to the "Lesley  Guest" SSID

2. Most devices will popup a registration webpage to login into the network from.  If you device doesn't open a web browser and navigate to any non ssl webpage( http not https) and will be redirected to the login page.   Such as

3. Click where it says Sign In

4. Enter the username and password you were given, as well as accepting the terms of use, and then press Log In

5.  You should now have access.  If you don't try disconnecting and reconnecting to the wifi network to refresh the connection.