Okay, let me try to give you an example for a typical traffic report:

At first you'll have to create a report template. Go to "Report Templates" and then click on "add". Select a data template - in our case "Interface Traffic" - and then click on next.
Now you will see a new screen "Template configuration [new]".
Type in a name for your template, maybe "Traffic (avg)" and choose the consolidation function "average". Save it now.
Now you will see two blue hyperlinks in the top right corner. Click on "Create a new measurand" to switch to the measurand configuration.
Use as name "Average traffic in Bits/s" and type in the abbreviation "avg". The unit should be "Bits/s", visible = "on", separate = "off" and then choose "Decimal SI-Prefixes ..." under rounding.
Now it will become interesting:
This measurand should return the average of all measuread values during
a reporting period for every data source of your Round Robin Database.
(In this case we have "traffic_in" and "traffic_out".)
Therefor we can use the formula "f_avg". Normally a rounter counts Bytes not Bits so we've to multiply the value with "8". So use as formula:
"f_avg*8" without quotation marks. Save it. Then you'll see a table called "Measurands" with one row that contains your new measurand. Click "add" and do the same way again for a measurand called "Maximum" with "f_max*8" and maybe "f_min*8".

After all these steps click on the yellow hyperlink on the top of the table "measurands". You'll get to the template configuration again. Set locked="off" and click "save".

After that we've to create a new report configuration.
Click on Management -> "Reports" and then on "add". Select our new report template "Traffic (avg)" and click on "next".
At this point you can follow the old powerpoint presentation step by step.

I hope this will help you until I'll find the time to finish the admin guide. At the moment I'm solving the last bug fixes for the upcoming version v0.5.1

Best regards
-Andreas-