Joint Seat Allocation Authority (JoSAA) will hold the JEE Main 2018 counselling and seat allotment for all the qualified candidates of the engineering entrance exam. To be able to participate in JEE Main counselling and seat allotment 2018, candidates will have to register themselves first and then follow the step-wise procedure of the same. The counselling and seat allotment of JEE Main 2018 candidates will be conducted on the basis of their merit, choice filling and availability of seats. During seat allotment, JoSAA will first allot the seats to candidates in two mock rounds. This will help them to know the seats, they could be allotted on the basis of their choice filling in JEE Main. After mock rounds of allotment, seven main rounds of seat allotment will be conducted for candidates.

Vist this link to know more about how the proceedings will take place

https://engineering.careers360.com/articles/jee-main-counselling-seat-allotment