M.Sc Preparation

You can certainly take up the UPSC preparation course along with your degree studies which is called a foundation course. You will encounter a challenge to maintain the time accordingly but for a suggestion (like most of the students are doing that I am in connection with), you may go for coaching at weekend basis and manage to revise your coaching matter for that weekend slowly during the entire week keeping in sync your regular college studies, this kind of management really works well. Thousands of students are preparing of UPSC right along with their high school studies or from their UG itself, so do not lose hope and go for it.

Yes, preparation for MS would be better if you have started from 5th semester onwards. So it's high time to prepare.

For Sri Venkateswara University Common Entrance Test 2018, SVUCET exam pattern and syllabus, click below
https://ask.shiksha.com/their-is-only-one-question-paper-i-see-how-to-get-more-qna-5148865?referenceEntityId=5149791.

Hello,
First of all, clear all basic concepts regarding particular subject.
Solve previous year Q paper.
There are different M.Sc Entrance exams like, IIT, JAM, TIFR, GS, Pune University exam etc., which you can apply.
There are some online tutorials like: -chem academy, Edu Rev etc. This will help you a lot.

There are a number of books, which you can actually read to understand the subject thoroughly. For basic, you can refer Watson or Lehninger.

Each of the premier institutes has their past papers over the website. The format and level of each of them varies. So, I would consult you to check the respective websites for your preparation.