@divafern hey, no problem at all. I think the problem is the way you're opening the sketch. Adam did things in a slightly 'advanced' way. So what you're going to want to do to open the source code before compiling it is download and extract the whole repository from here first. Then from Arduino, do File => Open and navigate to the Fairebot subfolder and select the Fairebot.ino file. When you do that, your Arduino window should end up looking like this:
The key difference here is there are those three extra tabs (eeprom, motion, and notes) that come along for the ride when you open it that way. When you hit compile in that condition, you should get it to compile without errors. That is definitely confusing, don't feel bad!