I have NO idea what I’m doing!

If you’ve got a Batch IX MakerBot all the surface mount boards should have arrived pre-soldered.  This means the first actual material step to building the robot is to solder the opto-endstops.  These are little circuit boards that contain optical switches that will prevent the machine from moving the build platform (and print head?) too far in a particular direction.  You can find the kits for the opto-endstops in the MakerBot store.  According to the page for these kits:

An optical switch usually used to detect when your robot has reached the minimum or maximum position of travel.

An optical endstop AKA opto endstop is a switch made out of light. When something interrupts the light-beam, then it signals the motherboard. Useful for detecting if your robot is attempting to self-destruct. ;)

Also, there are no moving parts to wear out, so they will last pretty much forever.

So, when all is said and done, hopefully I will have taken this:

OptoEndstops Parts

To this:

OptoEndstops v2.1