Can you just pick an existing real drum with the same timesig you need.
Set the tempo in real band the the same tempo as the wav/wma.
Set real band to 2 bar offset.
Now drag the wav/wma into real band.
You can now see where the count-in is.
You can see where the pre fills and post fills are.
You can see where the A section is.
You can see where the B section is.
You can see where the A ending is.
You can see where the B ending is.
You can see where the shots are at the end of the wav file.

If you look in the text file it will show where the count-ins, fills, post fills, endings, shots.
The bar number is the last number on the end
pattern,Count-in,0,5,0,2,-1
pattern,Fill,A,0,0,1,18
pattern,Ending,0,2,0,2,45
pattern,Normal,A,8,0,6,3
pattern,PostFill,A,8,0,8,1
and the 2nd number on the shots
Shot,1,47,166,179,1,80;snare
these bar numbers will correspond to the real band bars.

Now create your drums on the track/s below to match the real drum track count-ins, fills, post fills, endings, shots.

Now all you need to do is copy the corresponding text file, and with the guide drum track muted mixdown your new drums from real band.
In the text file just change the wavename=xxxxxx_140_Style.wav to your drums/tempo name and save the text file with the same name also.
Remove any "barsblocked" in the existing text file.
Put them both in X:\bb\Drums\XXXXXDrums.
Now go to the drum picker and rebuild.
You will now see your new xxxxxdrums.

Just keep at it, you WILL get it, I betcha, it is just a bit daunting at first.

Biab Track Injector for Reaper
Free Biab Chord Picker Tool