Your pdf example does contain A3 paper size sheets and here's an example showing 4 plans on the same sheet labelled as 1:100 scale:

But the scale is not 1:100
I've attached the same page from the pdf into your layout drawing and I purposely showed your floor plan stairs.

Your stair width measures at 2.36m
The pdf car stall width shows 2.6m but that is still smaller than your stair width:

So you should inform your teacher that the pdf A3 sheet example showing 1:100 scale is not correct.
The way to get 4 plans to fit on 1:100 scale is to use A1 Expanded size sheet:



I also purposely positioned in paper space a graphics scale to show that the vport is properly scaled:
