Putting Stairs is the terrian

[ARCHIJEF2000]

Using slabs is fine , its relatively quick and will produce steps, in fact it must be the method of choice whenever unusual constructions are needed, however don't forget the Chief way.

You can take advantage of the property of stairs joining automatically to landings. Landings can be generated and placed independently. To make a landing draw a slab placing it in the location of the lower part of your stair :build/structure/slab, adjust its size. Build another and place it in a position to represent the upper part of the stair, make the width equal the desired width of the stair.
Right click on a slab, and select "convert to plain polyline", right click again and select "convert to landing", repeat the process with the other slab, in both instances you should set the Heights of the landings that are appropriate for your model. Now generate a normal stair between the two landings, they should join, if not just move the offending landing and "bang it up " against the stair till it does.
Adjust the stair by fine tuning the heights of the upper and lower landings. Lastly open the stair dialog and adjust its properties, you may want to eliminate the handrails, and the overhang of treads.
In my example the top and bottom landings have been given pretty much the same depth as those of the stair treads, and so become indistinguishable from them.



In my example the little hill I made has a concave side, and the stairs are kind of hanging badly. to fix this you could place another landing in the middle of two stair sections and adjust its height the make the stair follow the slope better.