Hello,

First of all to become IAS Officer you have to appear for UPSC Civil Service Exam, in 2018 the last rank allotted to IAS for general category was 92, this differs in case one belongs to reserved category, And yes, even with a degree in computer science and engineering you will be eligible to appear for the exam as there is no barrier of belonging to specific stream/ subject combination or even aggregate factor for that matter is not important in this exam, you have to be 21 years old and can appear even in the final year of graduation, UPSC is conducted in three phases mainly such as

Preliminary is the first Stage, it's a MCQs based exam with two papers and each one consists of 200 marks, prelims numbers are not added to final list, you just need to score the required cut offs against your  respective category.

First paper is GS Paper-I which consists of the following topic such as History of India and Indian national movement, Indian and World geography, Economic and social development- sustainable development, poverty,inclusion demographics, social sector initiatives etc,Indian polity and governance-constitution,political system,Current Events nationally and Internationally, General Science,General Issues on environmental ecology,biodiversity and climate change .

Second Paper is CSAT which is qualifying by nature, you need to score only 33% which is 66 marks out of 200, it includes following topics such as basic numeracy, comprehension, logical reasoning and analytical ability, general mental ability, decision making and problem solving, interpersonal skills including communication skills.

Mains is a second stage which it's more of a subjective type, you are required to write answers for Four General Studies Paper such as

• GS-I includes Indian Heritage and Culture, History and Geography of the World and Society,
• GS-II includes Governance, Constitution, Polity, Social Justice and International Relations,
• GS-III includes Technology, Economic Development, Bio-Diversity, Environment, Security and Disaster Management,
• GS-IV includes Ethics, Integrity, and Aptitude
• Two Optionals
• One Essay,
• Two Language Paper

In total there are nine papers in Mains, and each paper is of 250 marks, total adds up to 1750 marks.

Personality Test  is the last stage which consists of 275 marks.

One thing important to remember here is even though Prelims is MCQs based while Mains is descriptive one, an integrated approach towards preparation is always recommended, there is definitely considerable overlap with the subjects, but since Mains is writing based it's important that you have at least the basic knowledge of all the topics, you don't have to be an expert but a strong foundation is required here, and as I said don't ever think I'll prepare for prelims and then mains after I qualify first stage, this is not at all right manner when it comes to preparation of UPSC, the first thing is always go through the syllabus, this will enable you to know what to read and what to skip, and this same knowledge of syllabus will help you in choosing topics when it comes daily newspaper reading where you will know what are all the important topics, and thereafter go through NCERTs, and then move towards standard books, previous year papers, practicing answer writing, applying test series etc,  you will come to this stage obviously once you start the preparation.