You're a little late. But if you want some short, quick rules, then these are
a couple that I would take in with me (stored only in my brain, of course):
-- If something is not accelerating or moving at all, then all the forces on it
must add up to zero. That could even mean a hanging rope.
-- In a vertical rope, the tension in it is the same everywhere in the rope.
The tension is the weight of whatever is hanging from the bottom.
That's really all I'm sure of, based on your hazy, fuzzy description of
what you've been doing in class. I don't want to get into things that
you might not have learned yet, and confuse you.