You definitely have the mind set to program this, you just don't know the language yet. I know how that goes, it sucks at first, but you'll get by it. Look up the topic AS Main (or use google) and research the following,
- if statements
- custom functions (not as complicated as it sounds at all)
- variables
- onEnterFrame = function () { handler
As for percents, you could so easily do everything you want with functions.
If you already have an onEnterFrame handler, add xp++; just to test things. That adds 1 every code iteration to xp.
Outside of the onEnterFRame handler, after the closing }, create this function, it's custom.
function levelUp():void{
maxHp += maxHp * .1; //this makes your new max hp whatever it was before, + 10%
maxMp+= maxMp *.1 //same thing for mp
xp = 0; //setting the xp to 0
maxXp+= maxXp *.1 // same for xp.
/*stats up code could go here, or you could have a new function for stats up like this one and call it from inside this function. */
statsUp(); /*that's how you call function. If you made one called stats up, and increased stats, it would be called whenever you called levelUp() because it's called inside of levleUp(); */
} //closes the custom function, everything between the { and } belongs to only this function.
That's an example of a custom function, it just goes by itself somewhere on your timeline code, outside of the handler. If you want to make a function yourself, you just say function functionName(){ } and put your code for the function between it.
That's just a quick explenation, but if you read up on what I told you and mess with it a bit, you'll be on your way. It takes awhile to get good with it, but you'll be on a roll once you understand it. I have to go design a game myself right now before I go broke, it's a fun day job, but not an easy one hehe.