Hi there.
My older home (1957) has an outside entrance to the basement. The
stairwell enclosure seems to be just standard cinder blocks mortared
together. The steps also seem to be constructed of cinder blocks
topped off by a thin layer of cement where some of this thin layer of
cement has cracked and chipped away, etc. I also have two back of the
house window wells that are also constructed of cinder blocks. Some
of the tops of the above ground cinder blocks have eroded away and I'm
looking to replace that top row block(s).

Some of the tops of the cinder blocks of the stairwell enclosure (just
a few inches above ground level) have eroded away where it is time to
probably just take out that cinderblock and replace with a new block
(or replace the entire top row of cinder blocks (we're talking maybe a
total of 10 or 12 blocks).

What is the cement composition that I should use - sand mix, mortar
mix, etc when I reset new top blocks into the window wells and/or
stairwell enclosure?
Also, similar question as to what do I use to resurface the tops of
the steps that have that thin layer of cement that has cracked and/or
chipped away?

Thanks,
Walt