For an technical intro for word2vec (what's that exactly, how to train it): https://lilianweng.github.io/lil-log/2017/10/15/learning-wor... and its readable implementation in PyTorch: https://adoni.github.io/2017/11/08/word2vec-pytorch/.

And just for getting idea why does it work, and play with examples in your browser: http://p.migdal.pl/2017/01/06/king-man-woman-queen-why.html