How to do error analysis in this lab on linear motion

[Binibini]

Okay so I did a lab on Linear Motion using the glider with the air track and a spacer. This is the information I have about the glider and spacer.

glider mass = (468.7 +/- 0.02) g
thickness of spacer =(14.8 +/-0.05) mm

I'm stuck on doing the error analysis and I don't know how to go on about analyzing the graph then finding the uncertainties. Here's the graph that I printed out from LoggerPro.

 

[Binibini]

anyone? i really need this, I've completed everything else but the complete calculations for analysis and data, i just need an idea on how to approach the calculations. I'm getting confused looking at the computational guide for uncertainties =(