"The large shirt is white."
Translation:La granda ĉemizo estas blanka.
The course does state that word order in Esperanto can be generous. However it's important to note that for clarity's sake you need to have your adjectives in certain spots. "La cxemizo estas blanka granda" would mean The shirt IS white big. The adjectives are both coming after estas the state of being verb. For what you're saying to work you would have to have kaj in there to make it "Blanka kaj granda" But then you'd be saying the shirt is large and white and that's not what you're being asked to translate.