To assign a keyboard shortcut to launch a program, you have to go into the menu.
Right-click on the menu launcher in the lower left-hand corner. You should see "Edit Applications" in the context menu that comes up. So choose that.
You'll see a window that is titled "KDE Menu Editor". In the left panel, you'll see a tree view of your applications; it looks more like the Classic menu than the Application Launcher. Konsole is under "System". So find Konsole there, and left-click on it.
Now, over on the right side, you'll see a panel with two tabs, "General" and "Advanced". Click on "Advanced", and then at the bottom you'll see "Current shortcut key" and a button that probably says "none". Click on it, and "none" will change to "input". Then just hit [Ctrl]-[Alt]-[T] on your keyboard (that's the keystroke combination you wanted, right?). Close the Menu Editor and you'll be prompted to save your changes. Save them, and you're all set. The shortcut will start working right away, you don't have to log out or restart or anything.
Shortcuts for things that aren't applications are mostly in System Settings under "Shortcuts and Gestures". But I don't know very much about them, so I probably shouldn't try to explain. I hope that helps with the application launchers, though.