To place a call, start by either entering the phone number with the dialing pad, or navigate to a save contact. When you have the desired number or contact ready, simply press the call button.
Answering an incoming call will differ slightly depending on whether you have a smartphone or feature phone, but generally, you'll just need to press or swipe the answer button as the phone is ringing.
Some feature phones have a slider or flip design. Opening these phones will answer an incoming call.