Hello - welcome to the Linux Mint forums
For Mint 13 KDE try this:
Right-click panel > Unlock Widgets
Right-click panel > Panel Options > Add Panel > Default Panel (or Empty panel if you want to start from scratch)
Or another way:
Click "cashew" in upper right corner of desktop > Add Panel > Default or Empty Panel
Click on the "cashew" (Panel Tool Box) in the corner of new panel > Add Widgets.
Click each item you want, then drag it to desired location on new panel.
(To see the open programs and folders you need "Task Manager" widget)
To prevent the clock and System Tray from going over to the left side of the panel, try adding a spacer.
Click "cashew" again > Add spacer. Drag it just to the left of the System Tray.
Right-click the spacer and check "Set flexible size"
When finished customizing panel the way you want, right-click "cashew" > lock Widgets
If panel is at the top and you want it on the bottom, unlock Widgets as before, click "cashew" > hover over "Screen Edge", click and drag the panel down to the bottom
of the screen.
Hope this helps -