IISER provides admission on the basis of 3 channels like -

Kishore Vaigyanik Protsahan Yojana (KVPY) – Candidates will be offered admission on the basis of valid KVPY fellowship.

State and Central Boards Channel (SCB) channel – Candidates opting for this channel will have to appear in an aptitude test.

Joint Entrance Examination of Indian Institutes of Technology (JEE) channel – Candidates with valid JEE Main Advanced 2018 scores are eligible for direct admission.

As there is nothing declared for 2018 session but tentatvely the application window will be open in the month of May 2018 whereas IISER Aptitude Test will be held in fourth week of June, 2018.

Also, the level of exam varies year to year so this is quite difficult to tell about its difficulty level like what it will be in 2018 but it is advisable to practice the previous year papers as this would be helpful for you to learn all important questions.

You can check all about its placement below -

Placement of IISER

Good Luck!!!