"...does the NTP client service have to be started or not?..."
Yes, it has to be started.
"...do we just put in NTP servers..."
This is necessary too, ntp-client need to know the source of accurate time.
"...and set time?..."
Not needed. NTP-client will set the correct time itself, after contacting ntp-servers a few times. If you need more info about how ntp is working, please read documentation section on ntp.org.