From what I remember once Absenthe does it magic it should add a Green icon labeled Absenthe. Tap that icon. Some folks report receiving an error message others report that their screen remains blank. I did not!
The "reported" solution tap home, tap settings, tap general, tap network, tap VPN, tap on, and wait. You should receive " a configuration error occurred", tap OK. Your phone will reboot (this may take a few minutes) and the Absenthe icon will have been replaced with the Cydia icon.
Your phone should still be connected to your computer. Once the Cydia icon is displayed you can disconnect from your computer and have fun.
I hope this is helpful.
Mike