Here is a quick informational guide on how to start a conference on a Cisco conference phone.
Step 1. After the Cisco phone has powered on You can press new call to call your first person. (Remember # when dialing out to a local number) (If an outside number #1 when dialing out)
Step 2. Press The option on the right that says "More" 2 times until you see "Conf" on the left most option
Step 3. Dial the number you with to add to the conference. (This will place your current call on hold.)
Step 4. Once you get connected inform the second caller that you are adding them to a conference call and press "Conf" again. This should now add all users to the call and everyone should be able to hear you.