From the Contacts tab, tap the plus icon, the Add a Contact

 

Tap Customize a new contact

 

Set the first and last name of the contact, then tap Add phone number

 

Tap in the gray text to the right of the blue text and begin entering the number for the contact, then tap Done 

 

  

In the Contacts tab, expand the group that the contact is in, then tap the contact entry

 

Tap Edit in the top-right corner

 

Make any changes you wish to save and tap Done

 

In the Contacts tab, swipe to the left over the contact entry and tap More

 

Tap Remove from contacts

 

Confirm by tapping Remove