Hi, A1Mom, you are doing great and it looks like you got great help right off the bat. I am inspired by your brave endeavor, and that's why I'm here. Soylent's directions were impeccable, and his photos were better than any I've ever seen; they show all the connections clearly, and you can easily see the distinction between the hot and neutral wires on the white and brown cords. If you can identify these and the hot and neutral terminals to which they attach, you will have no problem with this (although making the the actual connections DOES require a certain amount of manual dexterity and patience). Other things you should get:
Get an "egg wiggler" - or make your own with a plastic egg, water, and shredded Depend diaper stuff - and put your thermostat temperature probe into it
Buy an Incutherm digital thermometer/hygrometer from incubator Warehouse for measuring both temperature and humidity
Buy a p-timer from same place: set it for 21 and it counts the days and hours down to hatch day, or set it for 18 and it counts down to Lockdown, then up to hatch day. Good for record keeping and problem solving.
Consider using a computer fan with a DC adaptor that you'll modify. The idea is to provide GENTLE air circulation, and it doesn't take much. Ask me if you have an interest and questions about this.
Consider making a jacket of insulating material (maybe foiled bubble wrap - Reflectix - insulation?) if your incubator does not hold its temperature well (mine doesn't).
Humidity trays? You want to be able to control humidity by varying the surface area of exposed water, and how often you need to add water by managing the depth of the water. I like how Hovabator has worked this out for me with their plastic liner, but I wish it had been designed to hold more water. This is a feature I plan to work on. You want to be able to easily add water, maybe even to remove it. BTW, I have opened my incubator to add water to increase humidity during Lockdown, and gotten 100% hatches, but I prefer not to have to do that.
When it comes to heating with light bulbs, remember that it's better to use a few lower watt bulbs than just one higher watt bulb. In addition to getting more evenly distributed heat, your project won't die if a single bulb burns out. Also, don't make the total wattage so high that too much heat continues to radiate from the bulbs after they've been turned Off at 100*; and they shouldn't be so small that it takes too long a time to bring the temperature back up from 99 to 100. Light bulbs have worked well for me, even red ones and small sign bulbs.
I would like to know how your turner works! I use one that was made for the Hovabator, and I've no complaints about it other than its price.
You've got a good project going and there is so much excellent help on BYC. I will be looking forward to learning how it all works out for you.