On the phone screen, in front of the extension number, you can see the number of calls you have missed.
Step 1:
Push the settings key on the phone (has a gear icon).
Step 2:
You should see 5 options. Choose 'Call History' by using the ring buttons to go up and down, and push the center of the center of green ring to select it.
Step 3:
After choosing call history, you will have a list of all the lines available to you. Choose the one you wish to see using the green ring.
Step 4:
Push the center circle to confirm.
Step 5:
You will see the list of all your calls, you can scroll down using the green ring. Selecting any of the listed calls will initiate a call back to that number.
Step 6:
Push the return arrow to go back to previous menus.
Step 7:
Alternatively, you can select 'more' to get more options, including the option to clear the list.