How can I start a Free Call with a friend?

To pull up your friend's KakaoTalk profile. 

1) Locate the person on your Friends list and tap to open their profile.

2) At the bottom of the profile, tap the Free Call button. 

3) Tap Voice or Video Call in order to start the call. 

From inside a chatroom:

1) In a 1:1 chatroom, tap the + menu. 

2) Tap the Voice or Video Call button to start a call.