It’s hard to tell from the assembly manual, but the Z-axis linear bearings face toward the center of the front and rear side faces of the printer.
Don’t do like I did here and put them in the front and rear faces.
Their placement is not documented in the assembly instructions, nor clear in the assembly diagrams. It wasn’t until I installed the gantry in the frame that I found that my placement was wrong.
I did exactly the same thing but I noticed my mistake after one rail. The instructions for the 2.4 leave a lot to be desired, luckily there are people like you who get people like me through it without much headache otherwise it would take twice as long to finish. Thank you!