Above is stair type 1- The typical riser and thread with the upper floor acting as the last step
Above is stair type 2 - The monolithic solid concrete stairs
So in this video i model 2 different kinds of stairs,
The first is the typical thread and riser type, note i always have selected in the type properties ' end with riser' this always uses the floor as the last step which i like, the other thing is you always need to setout a reference plane for the start of the 1st step and also one for the exact center of the stairs otherwise it does not snap to any sensible point(i wish stairs could be left or right justified not just center justified). Point to note, for advanced modelers it is important to close all the gaps such as the side of the floor around the stair opening, the ceiling bulkhead in the larger room to the north etc. see video for process to close these gaps.
The second stairs is a monolithic concrete stairs, apologies for the confusion in the video but i forgot to model the floor finish in the lower retail unit so the stairs appears not to fit quite correctly but it does.
Be sure and check out 'Inside the factory' for their recent stairs questionnaires which hopefully will be released in next years product.