The phrase "stairs steps" means the individual parts or sections that make up a set of stairs.
Sentences with «stairs steps»
Step 1) Cut pallet boards in stair step lengths as shown above for the Christmas tree branches. (divaofdiy.com)
By set of stair steps number 3, I was still gripping the railing and watching my feet carefully, but apparently that wasn't enough. (bowsandsequins.com)
This is why the temperature data appears as an upward stair step pattern, not a smooth curve. (cfact.org)