3) Have you tried looking in the newsgroup
comp.soft-sys.matlab, which can be found via the google - groups link.
4) Have you successfully completed the relevant tutorial ? There are many on-line
If you cannot find the answer to your problem in these four steps then go ahead and ask.
Please include which toolboxes you have available, why the above searches failed to identify a solution, and which version of Matlab you are using. Sample code would be nice, but if it is full of idiotic mistakes then expect a crisp response.
Please bear in mind this is a forum for professional engineers, not students. That means if you are a student you should not be posting here.