"You are walking."
spacerujesz, chodzisz, idziesz - are about one person (singular you)
spacerujecie, chodzicie, idziecie- are about more people (plural you)
iść - is to go/walk right now in a specific direction
chodzić- is go/walk in general, usually or about having ability to walk or to walk/ pace without direction
spacerować is to go for a walk/ to stroll