Q: "A man sitting on a crate plays the guitar." Does this mean that "He is dancing as he plays."?
A: no

Q: "A brown-haired man with glasses, playing a guitar in an apartment studio." Does this mean that "A man playing guitar."?
A: it is not possible to tell

Q: "a guy working on hard stairs." Does this mean that "The stairs are made of wood."?
A: it is not possible to tell

Q: "A girl does gymnastics on a balance beam on the beach with an amusement park and people in the background." Does this mean that "A girl does gymnastics."?
A:
yes