Required User Privileges: Company Admin
Note that a new activity always belongs to one (and one only) of the activity types previously created.
The first step is to click on Manage. A menu will pop up, where you can proceed to click on Activity Types under the Company headline:
Once in the Activity types overview, click the the Activity type you want to add a new activity to, and then click New Activity. Name the new activity and click Add.
Once added your activity will appear on the right side list under the Activity Type you have chosen:
From there you can click on it in order to edit settings for the Activity.