COUGH
Have a look at the manual for such text script commands as StartCutscene, EndCutscene, MoveCharacterBlocking, NewRoomEx, Wait and DisplaySpeech for starts, and you should get something basic done. Do the scripting tutorials also.
COUGHCOUGH
I guess no one can really explain to you, how an intro is created, because creating an intro surely depends on your game plot, imagination and know-how.
If you really need help on this, maybe you should give us more detailed information about what you want to do on your intro.
Okay, since we don't know about your game plot or anything else..... I will give you an example intro.
This is what I would do to get ready for my example game intro. (yours will be different I'm sure)
First, set the player characters starting room to 0. Then make a new room, and save it as intro . With me so far?
Now, the player will start in room 0, which is the intro room. Next, set his starting position to 120, 160. Set his script name to MAIN. Make anather character, starting in room 0 at coordinates 0, 0. Set his script name to VOICE. Make a background of a kitchen and put it in room 1. Find a sound effect that sounds like leaves rustling, save it as SOUND1. Find sound effect that sounds like a man being bound and gagged, save it as SOUND2. Make an object in room 0 that is the games title, Kidnapped, that is initially invisable. Make room 1 a van with you tied up in it.
Player enters screen, after fadein:
(you see the character in the middle of a kitchen)
DisplaySpeech(MAIN, "What was that noise?");
PlaySound(1);
DisplaySpeech(MAIN, "There it was again!");
DisplaySpeech(VOICE, "Time is up!");
FadeOut(20);
Wait(10);
PlaySound(2);
Wait(10);
ObjectOn(1);
FadeIn();
Wait(30);
NewRoomEx(1, 0, 0);
That would be my intro example.