Are these lectures valid for June 2017 exams? Also, the lectures start from chapter 7-13 and then from 17-19. Will the remaining chapters/lectures be added or what? Please let me know.
Yes they are valid (otherwise they would not be on the website 🙂 )
The remaining chapters do not involve calculations and are more background reading for you to read yourself (and much of the earlier chapters are really knowledge you should already have from Paper P3).