Hello
To become an IPS officer you need to clear UPSC Civil Services Examination. Which is a 3 stage examination consisting of Prelims, Mains and Interview.
First of all download the syllabus and the previous year papers to get an idea about the exam and its demands.
You can start your preparation with NCERTs of class 6 to 10 of Geography and Political Science. NCERT of 9th and 10th for economics. And 11th and 12th for History.
Then you can move on to advance books such as Spectrum, Laxmikant, G C Leong.
Also in the meantime read the syllabus of optional subjects and see which interests you most. Optional papers prove to be game changers for UPSC exam. So, choose the one which interests you most as you will need to read it in much depth.
If possible seek coaching in some good Institutes. Although it is not must.
It will be a long and challenging path so be prepared for frustrations at times. Have some hobby which freshens you up.

Follow this link for more information on UPSC examination
https://competition.careers360.com/exams/upsc-civil-services-exam

Good luck