To access study material and resources for the UPSC Medical Science Optional subject, you can follow the steps below:

1. NCERT Books:
- Start with the NCERT books for Biology and Chemistry from class 11th and 12th. These books provide a strong foundation and cover the basic concepts required for the UPSC exam.
- You can access these books for free on the official NCERT website or download them from the EduRev app.

2. Standard Reference Books:
- "Review of Medical Microbiology and Immunology" by Warren Levinson and "Robbins Basic Pathology" by Vinay Kumar are highly recommended books for Medical Science Optional.
- You can purchase these books from local bookstores, online platforms like Amazon, or borrow them from libraries.

3. Previous Year Question Papers:
- Solving previous year question papers is crucial for understanding the exam pattern and preparing effectively.
- You can find previous year question papers on the official UPSC website or in books specifically designed for UPSC Medical Science Optional.

4. Online Study Resources:
- EduRev is a highly recommended platform for accessing online study materials and resources for UPSC Medical Science Optional.
- You can visit the EduRev website or download the EduRev app on your smartphone.
- On the EduRev platform, you will find a wide range of study materials including notes, practice questions, mock tests, and video lectures for Medical Science Optional.

5. Coaching Institutes:
- Joining a coaching institute can provide you with expert guidance and access to comprehensive study materials.
- However, it is not mandatory and self-study with the help of online resources can also be effective.
- If you choose to join a coaching institute, make sure to research and select a reputed one with experienced faculty.

Remember to create a study schedule and allocate dedicated time for each topic. Regular revision and practice are essential for success in the UPSC Medical Science Optional exam. Stay motivated, stay focused, and keep referring to the recommended study materials and resources to enhance your preparation.