To fill the JEE Advance form for 2019 you must first be eligible for it.

Students can give JEE Advance if and only if they qualify JEE Mains. The last year's qualifying marks for JEE Mains was 74 on 360. The qualifying marks change every year. 

So if a student wants to give JEE Advance he/she must first clear Mains and qualify in it by scoring at least minimum marks required for qualification.

If you still have any queries feel free to ask in the comment section down. 

Dear Uttam, Indian Institute of Technology (IIT) Roorkee has announced that JEE Advanced 2019 will be conducted in computer-based mode on May 19 (Sunday) in two different sessions for Paper 1 & 2. The registration dates haven't been announced as yet. The tentative dates might be First week of May. Please go through the link https://engineering.careers360.com/articles/jee-advanced for more information.