Here you will quench the temperature to 0K for the first time.

Look at the NAMD input file: echo.conf, this is realized by

set temperature    0
temperature         $temperature

The simulation will run for different time steps for different 
students. You will first be assigned a value tau. Use this value
to replace 200 in echo.conf at:

set tau 200        ;# here you want to assign your tau value

Again you are going to get the temperature file by typing:

gettemp youroutputfile > temp2.dat