Hello,

You can go do a  google search to access those papers easily as there are many private sites that provides pdf of such papers.You can also buy a book which contains previous years papers as a hard copy.Keep in touch with the latest syllabus too.

I also recommend to search 'Ojee b.tech paper' on youtube as you will get a lot of videos which also provide the detailed solution of these papers in a step by step way for better understanding of each question.

All the best!