It would be nice if you could create a flange in sheetmetal with a sketch. Just like Solidworks does.
Now I have to make first a flange and than cut all the things I want.
In Solidworks when creating a flange you can edit the sketch and evenly constrain this sketch to other parts in the assy. Please have a look at that and learn from your collegeas software producers.
Or maybe I'm wrong and is another procedure better to do this?