How to make a storyline in Unity 3d help

How do i make a storyline, is it done by scripting and adding txt, when some event happens??

yup

Uhm… very very broad question, what are you trying to accomplish? If you want text to appear when something happens, then something like this would make sense.

Regard the following Psudocode.

if (player has reached the point){    //i would use a collider then put trigger on and use OnTriggerEnter
     Time.TimeScale = 0.0   // (to freeze the game) or just end the scene.
     Enable the GUI Text
     Do whatever animation or cutscene you want to run
     Put timescale back to 1.0 // or start new scene
}