LPU has not given any guidelines pertaining to admission on the basis of national tests. Best thing to do right now is to appear for LPUNEST and seek admission in B Tech CSE. However, you need to fulfil the eligibility conditions.

The eligibility for the program is Pass with 60% aggregate marks in 10+2 (with Physics, Mathematics and English) or equivalent, subject to qualifying LPUNEST.

Since you have already qualified JEE you would know the drill and preparing for LPUNEST won't be much of a task.

All the information pertaining to LPUNEST such as syllabus, previous year question papers, sample papers is given on the lpunest website. You can click on the website and get the required information. Hope this helps. Good Luck