Hi. My sincere apologies if this is a really dumb question, as it appears to be Syrinscape 1.01, but I just cannot make sense of this, or I am missing something blindingly obvious. I like to use existing Soundsets as a starting point for custom soundsets and moods. I make a Campaign, and would then like to add an entire soundset to that campaign. Am I right in saying that this is ONLY possible from the Campaign page outside of the mixer interface, by dragging soundsets to the campaign? I find that somewhat weird. I search within the mixer interface, find a soundset I like, and then have to go another page entirely to copy that soundset to my campaign. I would think this should be possible from within the mixer interface. However, Properties only states I must duplicate the soundset, after which I can only copy moods from that soundset, not the set in its entirety. Again, apologies if I am missing something blindingly obvious. Thanks.
Yes, campaigns (listings of SoundSets for that left hand column) is something that is managed here: https://syrinscape.com/account/campaigns/ It is a little weird, but this was an easy way of making sure those campaigns appear in ALL the players anywhere.
BUT, also, I thiiiiiiink you might be thinking about something else, and mixing it up a little bit? (not surprising = there is a fair bit of stuff to learn). 
What are you specifically trying to do. Maybe:
- duplicate a SoundSet so you can then add sounds to it. Customise the Moods. Copy other content into that? = You can do all this within the Master UI.
THEN, that becomes a SoundSet which might be copied into a Campaign.
Campaigns are just custom sorted lists of SoundSets you have access to = including any PRIVATE SoundSets you have made by Duplicating Official content (since you can’t edit official content, because it is official).
I hope some of that helps.
Ask more questions! 
So weird. About an hour after I posted my query, I found the Soundset Creation Tutorial on Youtube. On top of being very helpful, this series gave me a much better picture of Syrinscape’s workflow using Soundsets and all the goodies contained therein. So I have been watching you explain for a good two hours (practising and such). Now I read this, and it’s your voice I am hearing! Benjamin, thanks for your helpful comments. I was indeed mixing up a couple of things. I will be putting the master UI through its paces today, preparing a horrific game of Vaesen!