climbing stairs animation and crowd animation

Hello
I am working on an animation where I need to have a lot of people climbing stairs at the same times and going down as well. I know about crowd animation and is there on Blender a way to animate a crowd other than array?
Regarding climbing stairs I don’t seem to get the right way to do it… I just can’t get the character’s steps of climbing stairs… is there a tutorial somewhere, I looked on youtube without success, that explain the dynamics of the steps for climbing?

Study walk cycles, shoot references…

Thanks
walk cycle as long as it is on a flat ground it is ok, but soon as one need to sync the rest of the body with the escalation of stairs or other objects I just can’t find the right sync values to apply to the rest of the body … it is complex… I have drawings but that does not provide rigging mechanics…

Ok here is a link that helps for rigging the character and also for setting up the walk other than on a flat surface. http://www.blender3d.org/e-shop/images/essential/essential-ch6.pdf

Maybe this can help too https://vimeo.com/dblg

Thanks
As a result, yes this is what I am looking for, but from the search I did, all the solutions !i could find were for BGE and not traditional animation using rigging , IK, FK and so on…
I am trying to have a climb cycle so that I can repeat it over the stairs, but my character goes very fast out of steps, either inside the stairs or outside…
I know I have a problem with the ik but cannot find ou at this point… Will keep working on it…