Tokenization
In this section you will get the brief understanding of tokenization.
http://blog.kaggle.com/2017/08/25/data-science-101-getting-started-in-nlp-tokenization-tutorial/
Vector space model
Vector space model is a statistical model for representing text information for Information Retrieval, NLP, Text Mining
In this section you will get the detail understanding of vector space model
http://mlwiki.org/index.php/Vector_Space_Models
Stemming/ Lemmatization
In this section you will get to know regarding stemming and lemmatization theory part as well as intuition in python
https://www.guru99.com/stemming-lemmatization-python-nltk.html
https://nlp.stanford.edu/IR-book/html/htmledition/stemming-and-lemmatization-1.html
TF-IDF
In this section you will get the brief understanding of tf-idf theory part as well as intuition in python
https://www.onely.com/blog/what-is-tf-idf/
https://www.kdnuggets.com/2018/08/wtf-tf-idf.html
Naive Bayes Classifier
In this section you will get to know regarding naive bayes classifier theoretically.
https://towardsdatascience.com/naive-bayes-classifier-81d512f50a7c