Well the Candidate registration and Choice filling for academic programs under JoSAA will start from 16 June, 2019.

Candidates who would write AAT can fill their choices starting from June 21,2019, after declaration of AAT results.

Display of Mock Seat Allocation-1 based on the choices filled-in by candidates as on June 21, 2019, 17:00 IST will take place on June 22, 2019.

Display of Mock Seat Allocation-2 based on the choices filled-in by candidates as on June 23, 2019, 17:00 IST will take place on June 24, 2019.

Candidate registration and Choice filling for academic programs under JoSAA ENDS on June 25, 2019.

Round 1 results will be out on June 27, 2019.

You can find the complete schedule here.

https://engineering.careers360.com/articles/josaa-important-dates