You can not download any PAM's reference weapon training from the internet. If you have access to DII then there is an electronic copy of The Army Electronic Battle Box which has every PAM that you may ever need on it.
Your PSI should have a copy of PAM 5, And a copy of AOSP Vol 1 whether it be on paper or on CD.
All PAM's are 'RESTRICTED' in clasification and should be treated as such.
You should do a Practice Period before you go in to WHT's. Im sure your PSI's have figured this in to your training nights.
If you still feel that you are not too happy then im sure your PSI's will give you extra Training if you ask them.