I have a property that has an outdoor concrete stairway that leads to a
basement entrance. The steps run down below grade along the back wall of
the basement to a landing, and then by turning right one can enter the
basement through a door in the back wall. The landing is about 18 inches
above the basement floor level, so after entering the basement door, there
are 2 or 3 steps down to the basement floor.

What I would like to do is add a few more steps down along the back basement
wall, beginning at the end of the first landing (where the existing door
is), and then create a second landing that is about 18 inches lower than the
first landing. Where the new landing will be, I would like to add a second
entrance to the basement.

The present concrete steps and landing are bordered by a concrete block
wall -- one along the side of the steps, and one at the end of the existing
landing at the bottom of the steps. The new design will require knocking
out the concrete block wall at the end of the existing landing to continue
the new run of steps down to the new (second) entrance to the basement.

The existing landing has a floor drain that I think goes to a French drain
type of setup under the basement floor. It doesn't go to any sewer line.
What I think I would like to do is have the existing floor drain and the new
floor drain for the new landing go to a similar French drain type of setup
under the basement floor which also can drain into a new sump pump pit that
I will have installed.

If it's a straight-forward job, I may just go ahead and do it myself with
the help of a friend. Or, I could get some estimates from concrete
contractors and see what they say needs to be done. If the concrete
contractors know what they are doing and it doesn't cost too much, I may
just have them do it -- but I have a hunch that they will want a lot more
than I would want to pay when I could do it myself for a lot less.

The part of all of this that I don't know about is how the new landing and
new added concrete block surrounding and retaining wall should be built. In
other words, is there a certain type or amount of footing that needs to go
under the new section of retaining wall? And, is there anything special
that needs to go under the new landing, other than a stone base underneath?
Is rebar required anywhere?