Modding Help

I made my first mod yesterday, it worked great no size change it was perfect.
Anyways! I know there is PVMLA files.. And ANI_G files. But noone actually explain's what these files are or control in tuts. I know the PVMLA files are used most commonly but whats the other files do!? Could anyone give me an idea of what these files control.. Cause i think i need them to cross mod. Thanks

ANIBASE
ANI_G_GUN_CH = ?
ANI_G_GUN_BC = ?
ANI_G_GUN_NX = ?
ANI_G_GUN_SH = ?

CM_HND_NM_DF_GUN_CH = ?
CM_HND_NM_DF_GUN_SH = ?
CM_HND_NM_DF_GUN_NX = ?

CM_HND_SP_DF_GUN_CH = ?
CM_HND_SP_DF_GUN_SH = ?
CM_HND_SP_DF_GUN_NX = ?

CW_HND_NM_DF_GUN_CH = ?
CW_HND_NM_DF_GUN_SH = ?
CW_HND_NM_DF_GUN_NX = ?

CW_HND_SP_DF_GUN_CH = ?
CW_HND_SP_DF_GUN_SH = ?

PVMLA = ?
PVMLA_W = ?
PVMSH = ?

OLD GUN to NEW GUN

PVMLA_??? ==== ANI_G_???_
PVMLA_?? ==== ANIBASE
CM_HND_NM_DF_???_CH ==== ANI_G
CM_HND_NM_DF_???_CH ==== ANIBASE

That is basically how to have to switch them when they have different names
The other files normally don't have any effect.