I can't figure out how to make stunning and or slowing spells for my rpg map, can someone please enlighten me on how?

If by stunning you mean to make a unit still, then constantly move the unit ontop of itself, and to slow down a unit make a burrowed unit like a zergling constantly move below it. If it's an air unit, I don't think you can slow it down.

Also make sure you're using hyper triggers.

Ummmm... OK but how do i male it stun a person for a particular time period. eg. 10 seconds. and can you please explain how the zergling works? i dont quite get how.

1. Use a Death Count Timer to time the 10 seconds, and during that time, center a location on the unit and constantly move that unit from the location centered on it, to that same location.

2. Constantly moving a burrowed unit underneath a unit slows it down, so you constantly center a location on the unit you want to slow and keep moving the burrowed unit under it.

Oh yeah, and if you constantly move a unit to its location, no one will be able to attack it, I believe.
Instead, constantly order it to move to its location. If it can still escape the stun, move it to its location every half second or something.

You guys dissapoint me, If you want it to be really stunned, give it to neutral, then back again. Or constantly order it to the location with hypers, If you constantly move it to any location then the unit will dodge a large percentage of the attacks thrown at them. Your best bet is giving the unit to another player or ordering it.

To slow a unit down you can constantly move a ground unit under it or creating and removing an air unit over it constantly.
You can also use ensnare XD

Most units can easily get away from the constant ordering if you click enough, that alone is not enough, I usually use a combination of that and moving them back if they get a bit too far.

I got a new problem, i'm trying to recreate the light barrier spell from TS (only for practice of coures) but it wont work. i can get as far as the energy apearing, but they dont go away after. i used a death timer, but it wont work properly. and i cant get to the map to check the actual triggers (and its kinda complicated)

Okay...
To be honest, the Light Barrier spell is actually a Glitch that became very cool .. but here's why you can't remove them.

The "energy" is the unit Aldaris... it is a specialy unit as you cannot Kill it or Create it (altho you can remove it). It must be preplaced to use.
When the LM casts the spell, the Aldarises, which are owned by p11, and are at a corner of the map, are moved to the Light mage, and given to the player.
After the deathcount reaches the end, you Move the Aldarises back to a corner on the map, Give them back to another player, and do the post-spell effects.
(note: the post-spell effects are not aldarises, but normal high templars, which can be created and killed.)