Not sure about your question, but if you want a classification model for labeling, firstly you need some data with labels for training, otherwise it is a clustering problem. If you want to use LibSVM, this file (https://www.csie.ntu.edu.tw/~cjlin/papers/guide/guide.pdf) will give you a very practical and helpful guide. Actually, this is where I started to learn and use SVM. Hope can help you.
I agree with answer (above), that "unlabeled data" is rather clustering. But perhaps for "unlabeled data" you mean, that all data have same label ? In this case you should use LibSVM with s = 2 (one-class SVM).