Level up System doesn`t work!

One way to accomplish what it sounds like you’re trying to accomplish is to use 2 scripts. One script would apply to your character/player. That one would be like the one you linked to from the other question. It would handle how much xp the character has, how much is needed to level and what level the player currently is.

The second script would attach to each enemy. That script would hold a value for how much xp killing this particular enemy is worth (we’ll say xpValue) (you’ll probably want that to be an exposed variable for easy editing / balancing). When the enemy dies (where you determine the hp <= 0), you’ll want to add its xpValue to the variable from the first of these two scripts (the one that tells how much xp the character has).

Is this a question?

Exp and other that kind of data should be holded on player or specific manager.
Imagine if you will have 50 enemies, there will be 50 same exp variables + other data you will have. Every enemy is enough with single integer which represents his type(and probably health) ,from that you can find anything you want.