Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Zubair ahmed
see a lots of material is available both in offline and online mode we must find the most authorize source of information and most important is we must stick to syllabus every time. for this standard set of books can provide you the best knowledge required to make a strong foundation else different good source i.e. unacademy, eduncle notes, various you tube channels. ultimately it your hearty devotion towards the sources you choose. they all can enlighten you.