I am relatively new to Cakewalk products and home recording in general, so I don't know if this is obvious or not. I have the Sonar VS 100. I want to record mainly on the drum machines that Sonar has. I went to add new track, instrument track then SI-Drum Kit. It opens up the drum machine window and something I noticed at the top right hand corner was a keyboard symbol that said "Give all keystrokes to plug in" and i click enabled. Except nothing happened. How do I use my computer keyboard to perform on the drum machines and other virtual instruments that include this capability?

The short answer is don't do it, buy a MIDI keyboard, pads or other input device instead.
 
The long answer.
The "Give all keystrokes to plug-in" feature is for sending keystrokes that would normally be interpreted by SONAR as shortcuts directly to the plug-in instead. In order to use the PC keyboard as a MIDI input device requires a virtual MIDI keyboard and virtual MIDI cable. There are a few available on the internet but the better solution is to purchase, no matter how inexpensive, a real MIDI input device. Many of them directly connect to the PC via USB. Instead of using a MIDI input device, MIDI can also be entered in SONAR, albeit not in real-time, using the step sequencer, piano roll and staff views.

I'm  with scook.
The only computer keyboard controller I have used is Bomes Mouse. It has its place, I suppose, but setup is somewhat involved, and it offers limited control. And you have to purchase a license after a short trial period.
Something like this might fit your needs nicely:
http://www.musiciansfriend.com/keyboards-midi/akai-professional-lpd8-laptop-pad-controller
A dedicated controller is 1000 times more satisfying to play than faking it with the computer keyboard.

What I am trying to accomplish is to get drums going that I can manipulate without copying and pasting some preset drum beat. Robert, would you say the drum pad you posted can do the job? Thanks guys

As far as creating your drums, yes it would. For me, the best way to get an idea from my head to the track is to play it. That's where a drum pad or controller comes in.
Once your MIDI track is recorded, you can manipulate or edit the notes in the Piano Roll View.