Using RDA and use "group by"

I am fresh to RDA and trying to create my 1st report. I have a very simple sql query that I am trying to apply, I have issues constructing the "group by" clause but everything else I am fine with. I am using column type report and have been trying to use event rules to aggregate without any luck. I have not found precise documentation that guides me and what event type to use, how to use aggregate function. Thank you. 

SELECT  yamail, sum(ytphrw) / 100 from f0618                       

left outer join f060116                                            

on ytan8 = yaan8                                                   

where (yamail <> 'W2' and yamail <> 'GRT' and yamail <> 'W1' and