The year,month, day, hour, minute, second is compine in one string and pass to the functions.
The function then sets the rtc clock.
SYNTAX
void rtc.setYYMMDDHHMMSS(String);
PARAMETERS
String of format "YYMMDDHHMMSS"
The first 6 characters of the string, sets the date. for example for year 2016, month 05(May), date 24 is 160524
The last 6 characters of the string sets the hour, minute, seconds. For example hour 13, minute 45, seconds 01 will be 134501.
So all together will be
rtc.setYYMMDDHHMMSS("160524134501");