Im so ignorant please help me

What is blends? how different is blend01 from blend02
What blend XR -90 90 means
What LX means
What AX AY AZR means
What { event 2001 21 } means
Why need loop? Do game cant loop animations that not made for looping?
Are there any more attributes should i know?
Which tutorials are needed to master on goldsource animations?
Which tutorials are needed to master on goldsource mdl compiling?
What $cbox 0 0 0 0 0 0 means?
what ZR 0 30 means at a bone controller?

From CS gign.mdl

$controller Mouth "Bone01" ZR 0 30

$sequence "crouch_aim_carbine"
{
"gign_anims\crouch_aim_carbine_blend01"
"gign_anims\crouch_aim_carbine_*blend02*"
"gign_anims\crouch_aim_carbine_blend03"
"gign_anims\crouch_aim_carbine_blend04"
"gign_anims\crouch_aim_carbine_blend05"
"gign_anims\crouch_aim_carbine_blend06"
"gign_anims\crouch_aim_carbine_blend07"
"gign_anims\crouch_aim_carbine_blend08"
"gign_anims\crouch_aim_carbine_blend09"
blend XR -90 90
fps 30
loop
}

From HL zombie.mdl

$sequence "walk"
{
ACT_WALK 1
"zombie_anims\walk"
fps 22
loop
LX
}

$sequence "dieforward"
{
"zombie_anims\dieforward"
ACT_DIEFORWARD 1
{ event 2001 21 }
fps 18
X
}

$sequence "vent_c1a3"
{
"zombie_anims\vent_c1a3"
{ event 1000 1 }
fps 18
AX AY AZR
}

In the Half-Life SDK, I found an in-depth document that explains all of that.
I think it's called "GoldSrc Modelling Workflow". I forgot the explanations themselves, but you'll find them in there, as well as a lot of other useful info.

Thank you most of the information is there.
Ill report after reading, if it doesnt include all necessary information

Blends are two animations that are blended together based on movement. XR , YR, ZR is X, Y, and Z rotations. CS has a more powerful blend feature known as "9 way blend" which is why you see so many animations within the blend bracket which is why when you move around your playermodel adjusts their pose and gun with more dynamic than just standard 2.

ZR "mouth" 0 30 is mouth animation that moves the mouth in say 30 which is 30 degrees rotation maximum and 0 minimum (starting point). Other ways is body rotation which begins at a midpoint say -90 90 is a 180 degree range.

LX is linear movement extraction. Meaning the game will move the NPC based on how much distance was covered in the walk SMD; so for example if in 30frames of walking the root bone of the NPC moves forward say 100 Generic units (3dsmax) ingame the NPC will move 100 Hammer units. The loop is added so the animation knows when to loop back to the beginning.

{ event 2001 21 } events are animation events that happen on a specific frame. "2001" is "drop light body" which is a sound and its being played at the 21st frame of the sequence.

Cbox you almost never use so you can ignore it and , AX AY AZR, are deprecated commands that you can also ignore.

Lastly, I have carefully documented pretty much everything GoldSrc QC related here:
http://the303.org/tutorials/gold_qc.htm

Which tutorials are needed to master on goldsource mdl compiling?

Have I got the thing for you:
http://www.the303.org/tutorials/gold_mdl.htm

thank you <3 awesome work more detailed than hl sdk's manuel

And The303 saves the day. I knew someone would know about this. ^^