Hello Dear ,

If you have not studied well in class 11th or your concepts are not clear regarding 11th class topics ,you do not have to worry. Don't loose hope , it will not going to effect your 12 boards , if you will prepared well for 12 board exams.

>> Firstly,  make your study plan for 12 board exam preparation.

>>You must be well aware of the complete syllabus of CBSE class 12 before starting your exam preparation.

>>Then start from the topics that carry the most marks and get a strong grip on these topics.

>> Just try to complete your syllabus of 12th class properly.

>> Read NCERT books thoroughly.

>> Solve previous year questions paper as much as possible.

As there is not much time left for 12th boards,  Don't try to restart your 11th class syllabus , it won't help.

Stay motivated and have patience.....

Good luck for your exams !!

Hope this will helps you ....