This physics video tutorial explains how to find the velocity from a displacement-time graph. The velocity can be found by finding the slope of the X-t graph.
Motion Time Graphs:
https://www.youtube.com/watch?v=nUb7xfkc0Ac&t=4s
Kinematics:
https://www.youtube.com/watch?v=dHjWVlfNraM&t=1699s
More Physics Videos:
https://www.video-tutor.net/physics-basic-introduction.html
