How to learn composition from scratch is as follows:

1. Learn the basics of music. Understand the basic elements of music such as pitch, intervals, harmony, etc., as well as the basic rhythm and beats in music. You can learn these basics by studying instruments, vocals, or music theory books.

2. Learn music theory. Understand knowledge such as musical form, harmony, and tonality in music theory, which is the basis for composition. You can master this knowledge by studying music theory books or studying with a music teacher.

3. Learn composition skills. Learning composition skills includes how to conceive a work, how to arrange phrases and sections, how to use harmony and musical form, etc. You can master these techniques by studying composition textbooks or studying with a composition teacher.

4. Understand the music style. Understanding the characteristics and rules of different music styles, such as classical music, pop music, rock music, etc., can help composers better grasp the musical style of their works. Practice composing. Exercise your composition skills through actual creation. You can try to write various types of works, such as songs, instrumental music, chorus, etc., and constantly modify and improve your works.

5. Seek help and advice. You can seek help and advice from music teachers or professional composers, and improve your composition through their guidance and feedback.

Basic conditions for composition

1. Music foundation: Composing requires mastering certain basic knowledge of music, including music theory, harmony, musical form, orchestration, etc. This knowledge is the basis of composition and can help composers understand and construct musical structures to better express music.

2. Sensibility and imagination: Composing requires keen sensibility and rich imagination. Sensibility can help composers capture musical elements and emotional expressions in life, while imagination can inspire composers' creative inspiration and creativity.

3. Technical ability: Composing requires certain technical abilities, including playing musical instruments and using music software. These technical capabilities can help composers better express music, while also improving the production level and quality of their works.

4. Creative experience: Composing requires continuous accumulation of creative experience. By creating different types of works, you can gradually master the characteristics and rules of various musical styles, thereby improving your composition level.

5. Patience and perseverance: Composing requires patience and perseverance. You may encounter various difficulties and setbacks during the creative process, but only by persevering in your efforts can you create excellent works.