- Copy the app launchers you want from /usr/share/applications/ or ~/.local/share/applications/ to somewhere in your home or manually write them
- Right click on them > Activities > Link to the Activities you want to show them
- On your panel add a Folder View plasmoid and set it as follow:
(Location > Show files linked to the current activity)
(Filter > Show Files Matching and select ONLY application/x-desktop)
Now play with other options like icon, title, view etc as you want. The wallpapers are available on my profile on KDE Store as part of the “Plasma Activities series” and so you can download them directly from Plasma’s get new wallpapers dialog.
I hope you find this useful, ciao!