these questions don't really come up in the hsc themselves, but basically your working with diff and double diff.
So you have displacement, basically, easiest way to do this (for both graphs, well work with veolicty as it's first diff) is to diff it, determine the stationary points, and then double diff it, and dertermine their nature. From there, put the velocity graph under the displacement graph so that you have the same values vertically aligned.
Plot the stationary points on the graph. Then, before the stationary point, look whether the graph is slopping up or down, then draw it in. Do the same for after, etc. Don't forget your POI as well.
So then, you have your velocity graph, consider that to be your displacement graph for acceleration. So that when you do acceleration, you're working off velocity, not displacement.
As i said, i highly doubt this would come up in the exam, but it's possible.
There are a few questions about, and even i know i'll struggle with this if it comes up in the exam, but yea, the general idea is to work 1 graph after the primitive (as in work velocity off displacement, acceleration off velocity) not trying to skip steps (and do acceleration straight off displacement).