how would i make it so when the player reaches the level goal ( a trigger ) he would see a cut scene and then be able to play on the next level?
You can either script the cutscene yourself or use a cutscene sequencing tool.
uSequencer is a good sequencer, as is Aperture. Animator is a free sequencer; it may or may not work for your needs. These tools allow you to interactively build a cutscene, scrub back and forth to test it, and play it during gameplay.
If you script it yourself, you’ll want to write a script for your trigger object that implements OnTriggerEnter(). When the player enters the trigger area, OnTriggerEnter() should start the cutscene. Coroutines are a good way to sequence the action of a cutscene within code.
At the end of the cutscene, you’ll call Application.LoadLevel() or a variation such as LoadLevelAsync() to proceed to the next level. In order to load a level, you need to add it to your Build Settings’ Scenes in Build.
I would use a trigger to take the player to a new scene where animations are used. I’ve done this before and it works great.