i just noticed: english is your 1st language (says your info)...
EDIT: so, let me redo, step by step, what was proposed:
1) have yanflys plugins set in the right order. youre going to need damage core and buffs & states;
2) create a blank state, give it an icon, set it to auto-remove however youd like (or leave it there without decaying);
3) put the code below in its note box. ive added the counter to the code since i think youd like the player to know how many stacks are there.
Code:
<custom apply effect>
user._stackingDamage = user._stackingDamage || 0;
//limiting the stacks to 8 or adding one more
if(user._stackingDamage >= 8){user._stackingDamage = 8;}
else{user._stackingDamage++;}
//change ID below to fit your game
user.setStateCounter(ID, user._stackingDamage);
</custom apply effect>
<custom remove effect>
user._stackingDamage = 0;
//change ID below to match your state
user.setStateCounter(ID, 0);
<custom remove effect>
4) create a skill to apply the state;
5) create a skill to cause damage. put the code below in its note box. ive added a line that removes the state since the bombs will detonate
Code:
<damage formula>
//if changing zero below to 1, the skill will work without the state
b._stackingDamage = b._stackingDamage || 0;
//setting damage to be 500 per stack. change what you need.
value = 500 * b._stackingDamage;
//remove the bombs. replace ID with your state id
b.removeState(ID);
</damage formula>
6) test.
EDIT2: also, hit F8 whenever youre testing and something didnt work. the console might give you a hint of what went wrong.