hello, I'm going to complete my 12 th class (mpc) and how to prepare for upsc cse along with engineering ( aprox 4 years +)
It's very good that you have already decided your goal and want to work towards it right from the first year. The first step should be to select a good coaching as it is instrumental in your preparation. Since you'll be studying B.Tech, online coaching should work best for you as it will involve less traveling and will save time. You can either study from youtube or Unacademy, both are awesome.
Now, when you feel that you are through with the syllabus, you should take a test series and give loads of mock tests, and this point cannot be stressed enough. You'll also have to prepare for the interview and you'll have to increase your GK and make your personality impressive. If you follow these points then it's sure that you will clear it with flying colors!