Fermenting wort generates heat so make sure it is the wort that it as your target temp, not the side of the fermenter nor the ambient fridge environment.
Set the tempmate a bit lower, chill the wort a few degrees below your intended ferment temp and take a gravity sample before pitching. aerate the wort well before or just after pitching.
Measure the gravity sample with a thermometer before pitching, then do again when it is fermenting to see how much heat it generates. Adjust fridgemate if need be.
Use 2 packets of lager yeast.
Be patient and wait till FG is nearly reached, then bring temp up a few degrees. Leave for a few days, then drop the temp to near freezing. Hold for at least one week, more if you have the patience.
Bottle/keg, wait till the brew drops bright in the bottle, then sample and assess.
Don't expect too much from your first and don't give up if it isn't superb.
Be clean and sanitary and leave shortcuts for getting home from the pub on a cold night.