There are 3 channels in IISER - KVPY, JEE, and SCB through which candidates can apply for and candidates opting for SCB channel have to appear in IISER Aptitude Test 2018.

Also, there is no particular date declared till now but tentatively the registration window should be open in the month of June most probably in last week.

To know detailed information about the same, you can go through the below link -

https://engineering.careers360.com/articles/iiser-admissions

Good Luck!!!