Click on the Contacts button.
You will now be directed to a list of your existing contacts with a second tab for your existing groups. Click on the + in the lower right hand corner:
You will now be given two options to create new contacts, one importing from your phone, and two manually creating a new contact. Click on Import From Phone.
Once you have clicked on the I Agree button, a list of your phones contacts will populate. Select the ones you would like to import and click on the Import Selected button at the bottom of the screen.
Your contacts will be added immediately.
You may have to "Pull to Refresh" on your contact lists within Contacts and Messages to reflect the import.