To be precise it actually means ‘to go by foot, doing a walk’. It means that you go with intention to reach to some target and you do it by walking. In that sense it means ‘to walk’. Idę do domu ‘I am going (walking) home’, idziemy w góry ‘we are going to (walk, hike in) the mountains’.
On the other hand, it does not mean ‘to wander’, ‘to walk around’, or ‘to walk habitually’, for that there is another verb – chodzić. Chodzę wokół swojego domu ‘I walk around my house’, lubię chodzić po górach ‘I like to walk/hike in the mountains’.
No. Verbs of Motion actually do show the difference between Present Simple and Present Continous. So "Do you go to school?" would be "Czy ty chodzisz do szkoły?"
Actually, school messes up a bit with this distinction, because apparently "Are you going to school?" can be understood as "Do you go to school? (Are you a pupil?)" as well and thus translated as "chodzisz". But generally, it translates like this:
to go (on foot), to walk = chodzić
to be going (on foot), to be walking = iść
to be walking (without purpose/direction, just walking around) = chodzić
Thank you - and yes, "Are you going to school" can mean "Do you go to school" in English - so this is what confuses me. I can never remember which english phrase to choose when translating from Polish to English (and sometimes the other way for the same reason). :) Hopefully one of these tips will help it stick in my brain better.