I am unclear on how to create shortcuts in Shortcuts and Gestures. Please help me assign:

Start key to open the menu
Start key + number to open an app
Start key + M to minimmize all opened windows

i don't think you can open the application launcher with just the Meta key. by default the shortcut is Alt+F1. if you want to change it:

System Settings > Shortcuts > Global Keyboard Shortcuts > KDE Component: Plasma > Activate Application Launcher Widget

click on the item and then on the button with the current shortcut and input [press] a new one. one Meta key won't do. you'll have to press another key while holding Meta or other modifier key to set a new shortcut. once you're done don't forget to apply your changes. here you can also change the shortcut to Show Desktop [AKA minimize all windows].

as for the application shortcuts:

System Settings > Shortcuts > Custom Shortcuts
Edit [in the bottom] > New Group
rename it if you wish, set the flag on and select it
Edit > New > Global Shortcut > Command/URL
rename it, go to Trigger and set the shortcut, go to Action and enter the command to start an application. add as many shortcuts as you wish the same way and apply the changes. afterwards you can save and restore the group of your shortcuts with Export and Import.

Unfortunately KDE doesn't support binding just the super key directly, but there is a third-party utility you can get that will map hitting the super key by itself to alt+f1: https://www.kde-look.org/content/show.p ... ent=154569