The reason that there are so many ways of doing it is because all you are doing is creating a stable environment. There are many ways of doing that. You want a constant temperature from top to bottom of your incubator. Your eggs can be placed in an egg box either in a medium or on top of a medium. The egg box is used to maintain humidity levels.

I would encourage you to continue to do your research and see what fits with what your future plans are. I have an old freezer with flexwatt and fans. I keep bottles of water in the door and floor to help hold the temps stable when I open and close the door. I use 6 or 12 qt Tupperware containers for egg boxes (depends upon the number of eggs in the clutch). The method that I feel most comfortable with is the substrate-less method. I have a four inch fan blowing at all times to circulate the air and keep the temperature constant. Without a fan, the hotter air rises and you have a temperature variance from top to bottom.

If you are only looking at one clutch, then you might want to look at doing the small cooler build. Flexwatt and a thermostat can be obtained from ReptileBasics.com and the fan you need to circulate the air can be found at coolerguys.com. The build is not very hard and you don't need a lot of skill to put one together. Plenty of folks here can help.