After graduation i.e b.sc can I prepare for ias and then when I clear my ias then can prepare for mbbs. After that how can manage both?????

You want to take couple of detours. First after B.Sc, you want to appear for IAS. For that you should be appearing for UPSC.

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 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

Now let's say you also crack UPSC, if you want to study MBBS, you should appear for NEET. As of now, there is no upper age limit for NEET and so if you have secured a minimum aggregate of 50% in Physics, Chemistry and Biology, you are eligible for NEET. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST. Now the upper age limit has been put on hold. And we do not know how long that might be the case. But if you crack UPSC and become an IAS officer, you cannot study MBBS and work at the same time. You have to go on a student break, complete your MBBS and then come back and join your duties.