Observium newbie...

This maybe a question that has been answered a million time but I've not been able to find an answer.

I have an Avaya 4524 switch that is not in a climate controlled environment.  I wish to graph the temperature within Observium.

I know the OID is 1.3.6.1.4.1.45.1.6.3.7.1.1.5 and the calibration is .5 degreee.  ( ie. 70 = 35 degrees)  I can view this in the switches GUI and by snmpwalk.

I have confirmed Observium is using the correct MIB for the device. 

Can someone point me to a newbie guide.  (My php skills are minimal)