for fade ins you could look at the cuttext and titletext commands. alternatively, since you're using triggers, look at the bottom of the effects dialog and you'll see the "titles" bit. if you want a fade-to-black, choose text, type a space in the text bit, and choose "black out" from the effect drop-down. same for fade-from-black.
as for ending a cutscene, create a trigger with "type" set as "end #1". in the condition line put end_my_intro.
now decide when your cutscene ends. what's the last thing that happens? you'll need to sense somehow when that last action is complete, either with an area trigger, or a timer. either way, once the final conditions are met set up the final trigger with an "on activation" box reading end_my_intro = true.
the cutscene will now end, and the mission will continue. not a very clear explanation, but you should get the gist.