If you don't have a foundation, buy a book like "Fundamentals of Mechanical Manufacturing Drawing".

First of all, understand the point, line and plane projection relationship of three views, mechanical drawing standards, tolerance fit and CAD use.

There are many reasons for choosing engineering books from Xinhua Bookstore. You can also download a mechanical drawing textbook from the Internet (Baidu Library).

Starting from the three views, put points, lines and surfaces; The relationship between height, length and width is thoroughly clarified.

Then learn the standards of mechanical drawing and master the particularity of mechanical drawing, such as drawing and roughness.

Master dimensional tolerance, form and position tolerance, heat treatment, etc. I will go to the factory for internship during my study.

It is best to learn mechanical parts and understand mechanical parts such as gears and pulleys.

I wish you success ~