I bought Sibelius 5.1 and VDL2 and installed them. Great.... i couldnt use VDL2 at all. While I could play around with the keyboard built into the mixer i couldnt write anything interms of battery percussion because... i dot know why. The note heads are all messed up, and it doesnt work the way sibelius 4 did where I could type note names and get desired results. i bought an actual, physical, real midi keyboard and plugged it into my computer and VDL2 says huh?  please help!!! Im dying to write some marching music.

poor band director

The noteheads in the VDL/Sibelius 5 template differ from those in the Sib4 template. I would recommend you start by using the Sibelius 5/VDL template, which you can download for free from here:
https://www.tapspace.com/updates

Since you have made the plunge into Sibelius 5, it would make sense for you to upgrade to VDL 2.5 (it's only a $19 upgrade if you're a registered VDL2 user). Using that will enable you to host it directly within Sibelius, and allow you to use the methods discussed in the tutorial videos found here:
https://www.tapspace.com/support/tutorials/Sib51.html

The new mappings for Sibelius 5 template are found in the README file that comes with the template, and will tell you exactly which noteheads to use for proper playback. Every single notehead has been painstakingly documented here (much better than with the Sibelius 4 template). In my opinion, the time this will save you easily outweighs whether or not it's worth it to spend 19 bucks on the VDL 2.5 upgrade. Using a keyboard will always be way faster, but this is the best method to date in being able to use Sibelius [i]without[/i] a MIDI keyboard.

Once you have the Sibelius 5 template (free), and VDL 2.5 ($69), you'll have everything you'll need to work efficiently in the Sibelius 5 environment.