UPSC is a 3 stage  selection process involving Prelims, Mains and Interview which tests your personality test. Prelims has 2 Papers namely General Studies and CSAT.

General Studies has Current Events, History of India and Indian National Movement, Indian and World Geography, Indian Polity and Governance, Economic and Social Development, Environmental Ecology, Biodiversity and Climate Change and General Science.

CSAT has Comprehension, Interpersonal skills including communication skills, Logical Reasoning and Analytical ability, Decision making and problem solving, General Mental Ability, Basic numeracy and Data Interpretation.

You will need atleast to start preparing ahead of 1- 2 years. If you are in your 1st year, you cannot appear for UPSC until your final year. And so current affairs should not be your concern from the first year. But the rest of the topics you need to study each subject atleast for one hour a day. Now there are crores of people who want to appear for UPSC every year and there are equally crores of people dreaming to become IAS officers. The truth is approximately 10-20% of them actually end up becoming IAS officers. The rest unfortunately do not. So you should prepare keeping this in mind. It is easy to blame the distractions or busy schedules or shuffling between Engineering and UPSC preparation. But remember that it is your dream and if you want it to happen, you should equally work hard. Because UPSC exam is not like cracking a jackpot, you should work on it. And practise atleast one sample paper a week. Will keep you up in your preparations. Select an Optional subject from now so that you can also work on it from the beginning.  If you are preparing at home, you need to keep yourself away from distractions and focus on the goal ahead. Gather as much as information as you can on each topic and keep yourself updated. Practise mock test papers.

Indian Polity for Civil Services bby M. Laxmikanth

Indian Art and Culture by Nitin Singhania

Certificate Physical and Human Geography by Gog Cheng Leong

Oxford School Atlas by Oxford Publishers

Indian Economy by Ramesh Singh

Economic Survey by Ministry of Finance

India Year Book

A Brief History of Modern India by Rajiv Ahir