If you haven't learned the basic knowledge of colored lead painting, I suggest you read some textbooks of Le Feiniao, such as Introduction to Colored Pencil, Warm Hand Painting with Colored Pencil, Self-taught Bible with Colored Pencil, Introduction to Colored Pencil Painting is Enough, Gourmet Painting, Carnique Painting and Flower Painting. You can choose one or two courses for self-study according to your preference. Most books contain colored lead.
If you have a basic knowledge of painting, I suggest reading the colored lead books written by Xiaomi, Shishi and Muer. The painting style is exquisite and realistic, but there is no basic theoretical knowledge, which is suitable for a little basic learning.