Below is a timelapse of our MakerGear Mosaic build. We should have a comprehensive review of the Mosaic finished shortly.
Before you run it for the first time, make sure to apply some machine oil to your rails and rods. It will run much smoother.
The kit comes with end-stops for each axis, but no end-stop mount for X or Y. We recommend these endstop mounts, which you can print immediately then install, making your life much easier.
On ours, the Z axis coupling tends to slip a bit if there is too much weight on the print bed, or if you try to accelerate the Z axis upwards too quickly. Try flatting the motor shaft before you put it all together. Here are some great instructions on flatting motor shafts yourself.