How can I prepare IIT JEE from the beginning for 2017 and how many questions are there in IIT JEE Mains..???

It is important to know as many details about the exam you are going to give as possible. For example, the syllabus, the exam date and paper pattern. Next set your daily routine and keep a fixed time for studying for your entrance exam. Pick chapters in the order of their importance. The right order of the chapter depends on the time remaining for your exam. If you have more than 6 months, you can revise the chapter in the order they are taught in school.If you have less time remaining, and you need to revise the whole course then study the most important chapters first. After completing any chapter revision is must. Solve previous year questions papers, MCQs and mock test papers to know your strength and weakness. There are total 90 questions in JEE Mains paper 1.