There should be a Windows key on this keyboard.
Is it a USB model or an older PS/2 model?
If it's a USB model, to quickly add a Windows key, enter the default layout (Windows mode) by holding down the equals key and tapping the "w" key (=w). The top four thumb keys, from left to right, will be: Ctrl | Alt | Windows | Ctrl.
If it's an old PS/2 model keyboard, there is an embedded Windows key which you can remap to the top layer. Depending on when it was made, the embedded Windows keys are either located in the "PrintScrn" and "Scroll Lock" keys (or for very old PS/2 keyboards they are in the embedded "h" and "n" keys).
You can easily remap these embedded Windows keys to a top layer thumb key by following the below instructions via Kinesis website:
Remapping bottom layer windows key to top layer:For PS/2 Contoured keyboards, the Windows key (or Command for Mac users) is located in the embedded "PrintScrn" and "Scroll Lock" keys. If you would like to remap the embedded Windows key to the top layer, follow these instructions:
1). Turn Keypad ON.
2). Press and hold the Progrm key and tap F12 (LED's on keyboard will flash rapidly).
3). Press and release the “PrintScrn” key. (LED's will slow down).
4). Press and release the destination key, for example- Right Alt (LED's will speed up).
5). Press and release the “PrintScrn” key (LED's will slow down).
6). Press and release the KEYPAD key.
7). Press and release the SAME destination key, example- Right Alt (LED's will speed up).
. Exit by repeating step 2 (LED's will stop flashing).
Now, in this example, the Right Alt key will function as the Windows/Apple Command key when keypad is ON or OFF.
NOTE: For older PS/2 Contoured keyboards, the Windows key is located in the embedded "h" and "n" keys.