Hello Sofia,

The method to create strand groups has changed in new versions, it is simpler and more intuitive now. In EditGuides you just have to select the guides in Strand mode, Turn On "Use Strand Groups" and click on Assign Unique. This function will create a unique group for the selected guides every time you press the button, you don't have to enter the value manually or create the Group channel manually.

As you can see in the gif below it is pretty simple:

All this information is in our documentation HERE.

"Also sometimes it is just greyed out and sometimes it isn't but when I tick "Use Strands Groups" it unticks automatically. Sounds like a bug?"

We have a similar bug a few months ago but this was fixed. Please update to the latest stable build if you haven't done yet.

PS: For better organization I suggest the creacion of a Guide Channel called "Partings", select the channel and follow the same instructions in the gif to create some groups, this way you have a separate channel for the parting only.

my ornatrix is not working right with the assign Unique. whenever i try to assign, it just apply the group to the entire thing?? please help, attach is a screen recording. 

hair from curve

I tried to ground them, but still not working. However, thanks so much for the interpolation options trick, that fixed it. but I need to return to the original later to get the sub-clump working. but at least those groups don't go away.