Distance measure using CT10s

Firstly I’m new to the Garmin golf watch so please be patient with me. To automatically save distances using the CT10s does my watch have to be set to scoring mode?
Also once I’ve selected a club and then played the ball when I approach where the ball landed and take out another club does the watch automatic record the previous distance on do 8 need to press the watch?

hope I made myself clear 

thanks 

Chris