Recommend that you will first upgrade to SCI 1.3, as it had improvements in Custom Reports.
Open Anaylzer Report
Choose AP Statistics Cube
Expand the filters section (click on 'No Filter')
Drag the 'Day' level into the expanded filters area
Select the day to be reported, e.g. select the 'Today' checkbox, and click OK
Drag the 'AP Group' level into the expanded filters area
Double-click the AP Group you're interested at, and click OK
Double-click on the AP MAC measure
Double-click on the RX Data Bytes measure
Double-click on the TX Data Bytes measure
If you're interested in the total traffic, create a custom measure out of RX+TX:
Right-click on Rx Data Bytes
Choose User defined measure -> Calculated Measure
In Name, fill in: Total Traffic (GB)
In Format pullbox, select "General Number"
on the right box, replace the content with: ([Rx Data Bytes]+[Tx Data Bytes])/1073741824
(the last part is so the result would be in GB instead of bytes)
a new summary column will now appear.
Choose which column you want the lowest 10 from (likely, Total Traffic), right click on its' header, and choose 'Top 10, etc'
Change 'Top' to 'Bottom', and 'by' to 'Total Traffic (GB)'
And you have it 🙂
You can now optionally remove the "RX Data Bytes" and "TX Data Bytes" if you're not interested to have them.