"a big and old office"
Translation:مَكْتَب كَبير وَقَديم
I suppose Seansei wants to know why the word order of the phrase above is not the same with the adjective order of the phrase in the previous lesson. Something like "مكتب كبيرقديم" means an old big office. He wonder to know why the order is different here, ie. big first then old but not old first then big.
So, the answer is: in "مكتب كبير وقديم" there is the وَ that expresses the equality. This Harf حرف makes qadiim قديم to be a ma3Tuf معطوف of kabiir كبير. So, قديم should come after كبير.
Don't hesitate to give me some feedback if you see some err in my comment. I accept any input :))