How to test data after training in Deep Autoencoder Network

I'm currently working on the deep network using autoencoder as per the following link. I trained the data with 44 features into 4 different classes and plotted the confusion matrix for the same. Can anyone tell me how to plot confusion matrix for validation and test data and also how to load them into the code given in the following link

http://in.mathworks.com/help/nnet/ug/construct-deep-network-using-autoencoders.html#nnet-ex20671592

[Hanan Hussain]

y = stackednet(xTest);

plotconfusion(tTest,y);

For reference:

https://www.mathworks.com/help/deeplearning/examples/train-stacked-autoencoders-for-image-classification.html?s_tid=answers_rc2-1_p4_Topic