Before doing this you need to Register your account (see Registering Greatascent).
Go to the Settings window by choosing the Greatascent Settings item from the Address Book menu.
First enter your account name. This is not your username but the subdomain part of the URL you use to access Highrise (ex. http://<account name>.highrisehq.com).
Then enter your user token. this is not your password but the token given to you by Highrise? You can find it on the 'My info' page in Highrise by clicking on the 'Reveal authentication token for feeds/API' link.
You also need to update this setting too when you regenerated the authentication token in Highrise.
Finally you must make sure that the SSL option is set correctly. The easiest way to do this is by logging in to your Highrise account. Then look at the URL if it starts with https:// and not http:// then you need the SSL option to be turned on.
Click the Done button to save your settings.
Go to the Registration window by choosing the Greatascent Registration item from the Address Book menu.
Drag your license file to the window that just opened. It should now say "Registered to <your name>". Restart Address Book and you're all set.
Use the key combination ⌘R or choose Refresh Highrise Contacts from the File menu.
Select a contact then use the key combination ⇧⌘T or choose New Task from the File menu.
Select a contact then use the key combination ⇧⌘U or choose New Note from the File menu.
Select a contact then use the key combination ⇧⌘I or choose Open in Highrise from the Card menu.
First select the Highrse group from the left. Then create a contact Just as you would do normally.
First create a contact as you would do normally. Then drag the contact to the Highrise group.
Select a contact and press the edit button under the card.