You have art on Tuesday
"un dessin" means a drawing, especially one you did using a pencil. "tu veux un dessin / tu veux que je te fasse un dessin ? Il faut te faire un dessin ?" is a somewhat disparaging sentence (sometimes threatening) intending to say that you're understanding nothing and that you have to leave / do as you were told.
The phrase 'le dessin' may mean the design. In the word-by-word translation, the definite article 'le' means 'the'. The noun 'dessin' means 'design, scheme'.
on Tuesdays I have ...
le dessin
The drawing.
drawing, artwork
Ratatouille, that's the movie, an animated movie.
Tu es le meilleur means "you're the best" in English.
Tu as quel cours le matin means "What courses do you have in the morning?".
doué dans le domaine de dessin
Marcou. has written: 'Le dessin et ses techniques'
tu me donnes le sel > tu me le donnes