SOLVED:When trying to enter in our 'cb activity' frontend box, nothing is saved.

It could be because I haven't found any examples or documentation for how to set this up?

Read the parameter descriptions carefully. The descriptions explain exactly what each do. I went into as great as detail as necessary for each. Especially the Asset parameter, which includes several examples.

So what you are saying is that I can create a specific 'asset' like module.[module_id] (is that a number or a placeholder?).
And then let the auto action post to that asset?
And then I can move all the current posts to that asset?

Please read the asset parameter description. Asset determines location. What stream you are storing the comment, activity, etc.. to. If it's profile.42 then you're storing to the profile of user 42. An activity stream with that asset will output all activity with an asset of profile.42 and will store new activity with an asset of profile.42.

Ok, so I created a module.[module_id], I think I'll give it a fixed number, so it doesn't change if the module changes.

You can use whatever asset you like. It doesn't have to be module.[module_id]. It can be more specific to the purpose of that stream. So for example if the purpose is birthday notices then I'd just set the asset to "birthdays".

And how do I move the current entries to that asset?

You can use the "Batch Tools" in CB Activity > Activity and mass change all their assets.

Ahh, og, so its actually just a free description, gotcha.
And the batch tools worked perfectly.
It's now called 'opslagstavlen' (bulletinboard).

You can also use multiple assets, but only the first asset will be used for storing new entries. Example as follows.

profile.42,profile.32

The above would display all activity from profile.42 and profile.32, but new activity created from that stream will store to profile.42 since it's the first asset supplied.