Help with modding

Hi all...
I'm totally lost with modding; i was trying to do a sniper whitch 1 shot and semi auto as many men make (I use the Silverfox's one^^).
I am lost with all the LTB files because i don't know what they are and what they do...
Is one for accuracy or anything...?
If someone can do a list of all theses files (example :CM_HND_NM_DF_***_CH) and their functions or just explain me it will help me so much
Thanks all =)

im sorry but i dont know a shit about moding..i just use them xD

ltb files are the models not the skills of the weapon just rename l96_pvmsh.ltb
to m16_pvmsh.ltb just to show you how !