Hi

First of all IAS  is not a course to have a duration, rather IAS is a service in which you can get by qualifying UPSC civil services examination

Your UPSC civil services examination consists of three stages

*The first stage of the exam is Preliminary examination (objective )
*The second stage, Mains (written).
*If you manage to clear mains then you are to go through third stage i.e interview/personality test .

To be eligible for UPSC civil services examination you need to be a graduate in any discipline and at least 21 years old.

And

it completely depends upon you how much time you take after graduation to clear the  UPSC examination as there are many candidates who qualify UPSC in their first attempt after their graduation while there are many who take 3-4 attempts and then qualified and there are some also who are not able to make it even after that.

But don't worry if you prepare well you can definitely  clear UPSC in your first attempt after your graduation itself and can become an IAS officer

To start your preparation  first of all go well through syllabus  , you can check the complete syllabus at
https://competition.careers360.com/articles/upsc-ias-syllabus

*Make a routine or a time table and try to religiously follow it , take short breaks in between your studies.
*Read newspaper daily and keep yourself updated with the current affairs
*Choose your optional subject wisely , choose the subject you have interest in.
*Make short notes .
*Revise :- there's no point of preparing for the exam if you couldn't recall anything in the UPSC Examination so you should stress on revision as well.
*Solve previous year question papers and mock test papers .
*Also work on your communication skills and personality development as it plays an important role in your interview round

For more tips go through

https://competition.careers360.com/articles/how-prepare-for-upsc-ias

If you have any other doubt then feel free to ask them :) we are always here to help you out and guide you

Thank you