A game with multiple levels

i am tring to make a game with 5 levels but i cant link the levels i made together plz help

You have to put something like a trigger that will move the level, using something like

function OnTriggerEnter(other : Collider) {
Application.LoadLevel("LevelName");
}

Attach that to a gameobject, set it as a trigger, and when you character or whatever hits it, it will load the next level.

You also have to customise the build settings to include all the levels you want in your game.

Try:

function OnTriggerEnter (other : Collider)
{
    Application.LoadLevel ("nameofyourscene");
}

If you don't want to use the name of the scene, but instead use the number/ order of the scenes you added in the Build Settings, you should do:

function OnTriggerEnter (other : Collider)
{
    Application.LoadLevel (1);
}

Check that link, it has useful information about Publishing Builds.