Are you trying to use these outside of the chart? Column A should be pretty easy, just take whatever aggregate function you are using and add the TOTAL modifier. If it's Sum(Sales), then Sum(TOTAL Sales) will get you the expression total.
Column B is probably more complicated, because I'm assuming it uses an aggregate function other than sum, which is why you need to change the total mode. If this is the case, then the Aggr() function is needed. The Aggr() function can be a little tricky, but it should do the job. You need your original expression and also all of the dimensions in the chart. If your original expression is Count(Customers), then you would need:
Aggr(Count(Customers), Dim1, Dim2.....)
Add as many dimension fields as you have in your chart. You may need to play around with it a bit depending on your data, but Aggr() should do the trick.
