dear aspirant i think your question is incomplete as guru nanak dev university provides various courses thus each can have different admission process and entrance exam syllabus . for example trhe admission  criteria for btech is completely different from that of undergraduation courses.even in some courses admissions are based on merit .so from the given link go through the eligibility criteria and syllabus of your desired course

https://collegedunia.com/university/25784-guru-nanak-dev-university-gndu-amritsar/admission

best wishes