How to demonstrate the method used to convert decimal to any other base?
You misinterpreted the video.
$\frac{N}{b} = x_3*b^2+x_2*b^1+x_1*b^0$
with a remainder of $x_0.$
To take a simpler example, consider dividing $14$ by $3$.
Then $\frac{14}{3} = 4$, with a remainder of $2$.
This implies that $14 = (3 \times 4) + 2.$