Hi @manas169014,

Already, you are in the right path and also follow the below:

• Start your preparation with ServiceNow ServiceNow Administration Fundamentals - ServiceNow University and complete all the associated labs as mandatory.
• Understand each concept clearly and practice those in your PDI, you can also refer YouTube videos as well.
• Study the eBook at least 2-3 times.
• Go through the CSA Blueprint - Credentials - Certified System Administrator (CSA) Mainline Exam Blueprint - Knowledge Portal.
• Practice mock tests in MeasureUP - NEW: Official Practice Tests Now Available for CIS... - ServiceNow Community.
• Also, refer Udemy and Exam Topics for more practice tests. Once you feel confident, attempt the exam.

Wishing you the best...!