Once you've downloaded "all_supreme_worlds.zip" from Dr. Lunatic Supreme with Cheese's itch.io page, you'll need to move all three folders (music, user, worlds) into the folder where you've installed the game.
Viewing post in Problem importing add on worlds
I'm not sure. I'll try again
If I delete everything and download again fresh, then I can start again.
I have no problem opening and running the basic SWC. So the issue must be in the add-ons.
Based on that do I need to merge both zip-lock folders together and then open them as one big folder? Or do I open seperately and then merge them?
This may not be related to the source of your problems, but for modern computers, Supreme has some issues in Program Files. If you've saved your Supreme folder there, move it somewhere else. Check "C:\Users\YourName\AppData\Local\VirtualStore\" (replacing "YourName" with your username and "C:\" with another drive if necessary) to see if your profile data and saved worlds have moved.
Also, "merging" might've been a poor choice of words on my part. There should only be the one "all_supreme_worlds.zip" from the itch.io page. Unzip that and move the three folders into your Supreme folder. When Windows asks you if you want to replace the files, say no. I'm not sure if replacing the originals causes issues, but I declined when moving the add-ons into my own game.
As far as I know I've done all you said.
Put the Supremeinstall file and the Allworlds file in my external hard drive.
Unzipped the Allworlds file. And then dragged it into the Supremeinstall file.
And it's still only the original worlds and about 30 extra worlds that were available in the Spismall in the standard game anyway.
Have noticed though that all the additional worlds end with the suffix .dlw and when I try to import them individually it says it can't open without me stating what I want to open them with.
Don't know if I'll ever solve this one my friend
I'm a little confused by the steps you took in your last post. Let me try to help you out.
Dragging "all_supreme_worlds.zip" into "supreme8_install.exe" won't work. The *.dlw files need to be in Supreme's "worlds" folder, which is a folder in the location where you installed Supreme. The *.dlw files won't open on their own or if you drag them onto an *.exe file.
To play the add-on worlds, you need to unzip "all_supreme_worlds.zip", which should contain three folders named "music", "user", and "worlds". Then, move the contents of those three folders ("music", "user", and "worlds") into their corresponding folders in the location where you installed Supreme.