Explanation:

The election to the President of India is an indirect election. The people do not elect the President directly. He is elected by MPs & MLAs who are in turn elected by people. The election process is based on the concept of Electoral College and the value of vote of MPs & MLAs is different.

Eligibility Criteria :

The following are the mandatory requirements for anyone to contest the election for the President of India.

Must be a citizen of India and have completed 35 years of age
Must be eligible to be a member of the Lok Sabha and not hold any office of profit under the Government of India or the Government of any State or under any local government.(Exceptions are the offices of President and Vice-President, Governor of any State and Ministers of Union or State)
Apart from the above conditions, the nomination paper of a candidate has to be signed by at least fifty eligible voters (MPs & MLAs) as proposers and at least fifty eligible voters as seconders.
Workflow of the election process:

The one major difference between any normal general election and the Presidential election is the differential value of votes of various electors (voters). In any normal election, the value of the vote of every citizen is the same. His/her vote is counted as one vote.

But in the Presidential election, the value of the MP vote is different from the value of a MLA vote. Not just that, the value of a MLA vote from one state differs from the value of the MLA vote of another state. The value of all the votes put together is the value of the voters for the election. Before each such election, the Election Commission notifies the total value of all the votes based on vacancies etc at that point in time.