how to label features to train by SVM?

i have to train SURF features which are stored in a excel file..what is the best way to label? i have 96x20 (48x20 for class A and 48x20 for Class B) dimension of features which i currently stored in a excel sheet..then i made another excel sheet and assign labels as A to 48 rows and next assigned 48 B labels..then i loaded both the files through xlsread in my program..

features_train = xlsread('A_B_features');

[num,labels_train]=xlsread('A_B_labels');

SVMStruct = svmtrain(features_train,labels_train,'Showplot',true);

is this the correct way for svmtrain ?? or should i keep my features and labels into a single file? if yes..how??