Going down stairs of climbing down can be drawn in many ways. The easiest way would be to simply drawn several panels and put the protagonist in a deeper spot on each panel.
One way to make this process in the story more intriguing to look at is by putting the panels as large vertical panels side by side as in the example below.
An author whose work I love very much, is Andreas. In my opinion, he does mind blowing stuff in his graphic novels.
For instance, in the image below, we see how the protagonist climbs down. But not in several distinct panels, but in one big image with what could be regarded as borders of panels on top of it.
The idea of using one image to display a process over time, is very ingenious in my opinion.
Even when using several panels to let our protagonist Rork climb down a stair, Andreas does something special. He draws the panels as if they form the steps of a staircase.
Other posts by me on Andreas can be found here: