sure. Running Totals is not my forte...DBlanks is the master.
Formulas, I can help with.
They tend to come in sets of 3: reset, increment, display. I would think that they are similar to SSRS and if you were running a custom variable.
reset, usually the group header:
shared numbervar x := 0;
"" //hides the zero output
increment, usually in the detail section
shared numbervar x;
if someCondition then
x := x + {table.field}; //usually a table.field, but could be a constant
"" //again hides the running total
display, usually in the group footer...and for your report, you may put all display in the group footer and suppress the detail section so that you get just 1 record per salesperson.
shared numbervar x;
x
just create the formulas, and drop them in the section that you want them to run in. Formulas will execute even if the section is suppressed, which may not be the case in SSRS, I know it isn't the case in other reporting system that I develop for.
HTH