I would like to know if you have a study on the Holy Spirit.
The only specific study of the Holy Spirit on the website is at Class: Questions, Lesson 12. There are many sources on the website that mention the Holy Spirit and His work in connection with other studies. For example, Question 138 and sources cited in that answer deal with alleged modern day “miracles.” Question 9 and this lesson on baptism deal with the baptism of the Holy Spirit, Question 14 deals with the gift of the Holy Spirit in Acts 2:38, and Question 20 deals with when the Holy Spirit is received. If you will study the sources available on this website you will undoubtedly find many other discussions of the nature and work of the Holy Spirit.
You Must Hear the Gospel
You Must Believe
You Must Repent
You Must Confess
You Must Be Baptized
You Must Be Faithful Unto Death