See for the PUBDET there are no strict syllabus provided. As per the official bulletin of the PUBDET 2021, the entrance test for the History Hons. will contain 80 marks question from History & 20 marks question from English. Now for both this subjects, you have to prepare with respect to the boards syllabus. Focus on the syllabus strictly for History & for English focus on the grammar and vocabulary portions. You can also focus on the NCERT History books of 11 & 12th as well.

Also I would suggest you to visit the link below, and download the last 3 years question of PUBDET and basing upon that start your preparation:

https://wbjeeb.nic.in/EXMPUBDETCMS/Page/Page?PageId=1&LangId=P

I hope this helps. Wish you a great day!