mini frig incubator

my parents have a mini frig that does not work no more and i want to turn it into a incubtor for when i start breeding reptiles. i have a few questions about it though. first where should i put the heat tape? top bottom sides? and if i should get compuer fans to circulate the airflow and how many? and also do i control it by cutting a small hole in the back and running the heat tape cord out that to the thermostat? any help would be appreciated

I would run the heat tape on the back and/or sides. 1 decent sized low RPM high CFPM Fan should be all you need to keep the temperatures good. You will need to control the Flexwatt with a good proportional thermostat.