Hi there, Welcome!
Looks like your on the right track with the things you've got. You'll want some wheels and of course something to build the chassis out of. You can buy wheels that fit the D shaft. Something like this is specially made to fit the shaft:
https://www.pololu.com/search?query=wheels&x=0&y=0
If you go to this ebay listing:
https://www.ebay.co.uk/itm/2x-10A-RC-Br ... SwrtVZrkx8
And look at the last picture along it contains a wiring diagram to help you see how to wire the ESC up. I know the model in the listing isn't the same as the one you have but the wiring is the same.
You'll need (well it would be better to but not essential) to modify the wiring so that both ESC are turned on and off by one switch. Some people just remove the switch(es) on each board and then connect the ends of the wires together where the switches used to be so they are 'always on'. You would then put a switch in series with the battery and control the on off from there.
You'll also want to set up the wiring so both ESC are pluggged into the battery (imagine a Y shape with the two + wires going into one wire then (via the aforementioned switch) to the + of the battery and from the - side a single wire coming out which then splits into 2 wires one going to the - of each ESC.
When it comes to the three colour wire connector this would go to your receiver. This wire provides power at a safe voltage for your receiver and also receives signal from the receiver which the ESC then turns into motor speed and direction. Check this site for the colour coding of the wires:
https://www.pololu.com/product/1046/faqs
You'll want to plug the three colour wires into the receiver. However I believe that for one of the ESC you will want to cut the red power line. This is because both ESC have what is called a BEC on them. This is a battery eliminator circuit or basically a device which turns the 7.4v from the battery into a safe 5v which the receiver can handle and not be blown up by. It is my understanding that if you have two BEC acitve, they can interfere with each other and cause issues. Hopefully someone else can confirm i've got that bit right, but basically we only want one ESC to use its BEC to power the receiver and we can achieve this by not using the +/power line from one of them.
You're right about it being one ESC per wheel.
A few other tips.
Make sure you're motors aren't touching when you power up as this could lead to a short circuit and some blown up electronics. Some have found those cheap motors have issues out of the factory so i'd suggest just test them with a battery first to see that they run fine.
Also those ESC have a little switch on them which turns on/off a funny braking feature which you don't really want enabled because it makes driving impossible. basically if you get it wired up and find it difficult to get the motors to reverse then just turn everything off and flip the little switch on the board and try again.
Hope that helps.
