It is a kind of hard thing. Please read this a few times. Because it is confusing (i think)

I have 3 electric-beams (switched off) and a door build and placed in radiant.
After the player have switched a button a script will run. That script needs to take care that the first electric-beam will turn on. Then the script will wait 2 seconds. Then the second beam is activated. It will wait 2 seconds again and the last electric beam will be activated. Then the script will pause 1 second and the door will open.

So the script step by step:
-activate first beam
-wait 2 seconds
-activate second beam
-wait 2 seconds
-activate third beam
-wait 1 sec
-the door will open

It is kind of difficult but i need help

BTW. If you can and you want it. Can someone also explain what the lines mean.

You basically have your script planned right there. Effects, that is, fx_runners, are turned on and off by using their targetname use("targetname") in the script. Waits are just waits wirth milliseconds. Maybe you want a toggleable door so that it looks better when it opens and stays open. With the fx_runners, just remember to check that they will not start on.

What you are asking is such an easy thing that it's hard to explain it in any deeper detail. It should be a breeze for you.

And how would a entity follow a path and stop at the end??? It think it is done to scripting to

An entity to follow a path? Hmm. Func_train? If you just want to move any arbitrary entity, your best bet might be a roff file. Naturally, you would need 3DSMax and a plug-in to make a roff file - or some kind person who would do the work for you.

Of course you can use the move script command like you do with elevators, but they don't really allow you to smoothly make an entity to follow a path (unless it's a straight path).