For the Previous year JNUEE papers you should visit the official website of JNU and fill up the necessary details in order to download the paper.

The link for JNUEE previous year papers :

https://admissions.jnu.ac.in/searchquestionpaper.aspx

Also for sample paper you may visit the link provided below:

https://university.careers360.com/articles/jnu-sample-paper

I hope this answer helps. All the very best for your future endeavors!