general question about fade updates

Hey Guys
i'm new to HOG so don't judge me :)

My cue consists of a beam time which is 1,5sec.
Which way to change the time via command?

I tried following when running THAT CUE:
-group3 enter
-beam time 0,5 enter
-update (kind mask set to time) enter

hmm..doesn't work.

How does it work?

Regards
Jay