knn classification with matlab

hi everyone i am trying to create sample,training and group classes to be used in classification with KNN but i have some challenges . i have 24 classes of images of which each class contains 100 images. feature extraction was done and i got a matrix of 2400*20736. how can i create the sample,training and group classes because as i read , class=knnclassify(sample,training,group);. any help will be appreciated.

[José-Luis]

Have you read the documentation? As stated, the question only invites a re-hash of the documentation.