Hello aspirant, 

I'll tell you few steps in which you will understand how to prepare for cat examinations 

1. Go through the CAT Exam Pattern.
2. Check complete CAT Syllabus.
3. List down your strong and weak topics and areas in all the sections.
4. Gather all the preparation material, apps, and books for CAT Preparation. 
5. Take as many mock tests to analyze your weak and strong areas.

You should devote 5-6 months to study and then, consistently practice for the test day. Divide your time for every section depending on the level of your current preparation. 

Follow these books for reference 

• NCERT mathematics books (6-10) 
• How to Prepare for Quantitative Aptitude for the CAT by Arun Sharma. 
• Quantitative Aptitude for Competitive Examinations by Abhijit Guha. 
• Quantitative Aptitude Quantum CAT by Sarvesh Verma. 
• Quantitative Aptitude for CAT by Nishit Sinha.

Hope this information helped you. Good luck