Analytics Software

Hello All,
How can I find the number of logins per day, No.of logins per dashboard, No.of logins per region etc by using usage tracking tables.
And what are the definitions of columns 'START_TS', 'END_TS', START_DT', 'END_DT', 'START_HOUR_MIN' and 'END_HOUR_MIN' in S_NQ_ACCT Table.

Thanks
Jack