In the first photo, you can see how the plywood support board is cable-tied to the threaded frame rods at the base of the printer. The X-end idler wheel is almost directly overhead. You can also see the Y motor in the background on the left.
The second photo shows the RAMPS board from above, with the USB connector on the left, which is ‘the right way up’. The corner of the board with the mechanical endstop connectors is at the top with X on the left, then Y, then Z. Note that when using mechanical micro-switches as endstops, there are no connections to the ‘+’ row (the six empty pins below the connectors). Note also that every second column is unused, as that is where maxima endstops would go, and we’re using minima endstops.
In the bottom of the photo you can see (blurrily) the Thermistor connector, connected to T0, with T1 and T2 left empty.
Right at the bottom of the photo (and even more blurry) you can see the connector for the Z stepper motors, and the crucial Red-Green-Yellow-Blue sequence from left to right. The motors will not work if you mess this sequence up at any point in the build.
Photo number three is upside down. That is, we’re looking from above with the USB connector to the right instead of the left. This makes it look as though the stepper motor colour sequence is reversed.
Don’t get confused. The sequence is R-G-Y-B when viewed the right way up, with the USB connector on the left.