Re-installed last night, was getting weird problems, openbox was taking around a minute to load from sddm, couldn’t work out why so I thought I would reinstall.
I did a manual partition in the installer, but it doesn’t seem to have created the expected sub-volumes. So can I create them manually and move stuff into them (/var etc).
Also can some kind person point me to an idiots guide?, I saw one months ago, but can’t find it now.
at least @ and @home should have been created. Is that so?
And of course you can create subvolumes afterwards. sudo subvolume create @whatever is how you can do this. Search the forum, there are some topics about the subject with plenty of information already 
Note: For a +++ non-encrypted version +++ of this setup follow the instructions provided in this forum post.
Thanks guys, will bookmark for the next install (when I fsck it up).
@T-Flips yes, I haven’t used btrfs for a few years, it screwed up really badly on me, when I was on Manjaro - it proper put me off 
But I believe this was a problem with TLP and supposedly fixed.