I am currently developing budgeting worksheets.

Sheet 1 = forcasted spend / actual spend
Sheet 2 = Monthly breakdown of spends in a classification
Sheet 3 = Full breakdown of spends, with expense and then a classification given

I would ideally like to only complete sheet 3 detail what has been spent on where and allocating a classification (e.g. event management, fliers etc.). Once this has been, I would like excel to calculate for instance all event management spends in May and put this on sheet 2 under May event management as a total cost. But I have no idea how to do it!! Any suggestions

(I hopet his makes sense)