First year perhaps you have to study courses in Physics, Chemistry, Mathematics 1&2, Mechanics , Programming and Data Structures and a couple of more courses depending on your Institute. In most of the IITs and NITs Manufacturing Processes, Electrical Technology as well as Engineering Drawing and Computer Graphics are major courses.

You have excellent Video lectures by distinguished professors at Top IITs and IISc Bangalore on NPTEL, which will help you immensely during first year and wil teach you the subject in depth. As a suggestion, Prof Somnath Bhardwaj , Prof Debasis Ray and Prof Jitendra Kumar from IIT KGP have recorded one of the best lectures of Physics , Chemistry and Mathematics respectively, with full playlist avaliable on NPTEL's YouTube Channel. As far as another dreaded subject of first year, Electrical Technology is concerned, Prof Debapriya Das of IIT KGP as well as Prof L. Umanand of IISc Bangalore have recorded excellent video lectures on the NPTEL Channel.

All the Best.

Hello,

Some of the good channels to follow are 5 Minute Engineering which will be taught in Hindi, if you are not comfortable then another channel is Knowledge gate, Khan academy, education4u, Easy Engineering Classes, Gate lectures by Ravindra and many more channels. You can search the desired the topic which you need explanation for that topic and can see many videos related to that topic, based on your understanding of the concept by that particular YouTube channel, you can subscribe to them for more updates on videos.