The attachment snipped as in your video shows First order kinetics graph as a decreasing curve and second order Kinetic graph as a increasing curve. Is this correct? Because in class we learnt them as straight lines. We did a Q 45 in Zumdahl and I learnt that st line graph decides the order of reaction and this doubt popped up in my mind? Can you please explain?

These curves indicate that reaction is zero order.
In class we have learnt that
[A] vs t is a straight line  with negative slope  for zero order kinetics because integrated rate law for zero order is
[A]_t = -kt+[A]₀

ln[A] vs t is a straight line with negative slope  for zero order kinetics because integrated rate law for First order is
ln[A]_t = -kt+ln[A]₀

1/[A] vs t is a straight line for second order kinetics because integrated rate law for second order is
1/[A]_t = kt+1/[A]₀