Is it where you do it in groups?? if so I did mine on an attic conversion for a family of 4 (i think). We had different headings like our introduction, (explaining the pretend family's living conditions and their reasoning for wanting one in the first place), we contacted different attic conversion companies and got prices, we had our action plan (cutting down the family's expenses, i.e. subscription plans), we compared and calculated different loans from banks (AIB, Bank of Ireland etc.) We had survey questions (mainly on interior desgin) based on the family's preferences and created graphs out of them, and we made their overall budget.
The most common idea for this CBA is a gamily holiday and i did one on a family hokiday in the South Of France. Here are some important headings i put in this....
Family finances. E.G saleries,their budget,credit unions etc...
Getting and comparing flights
Getting prices for transport in France. E.g trains,trams etc...
Getting and comparing the hotel prices
And many more
This CBA is done individually or in a group but id say this year its more likely as a group project as last year i did it individually due to Covid
Hope this helps ypu and good luck
We did ours individually on a family holiday to spain
importatn things to think of were things like where the family sat on the plane and activities suitable for a family whilst all In their price range