The basic unit of Chinese character writing, or sinogram, is the stroke. In Chinese writing, there are 8 fundamental strokes:

These 8 simple strokes can have many variants, 29 in total, called "complex strokes." However, it is not preferable to learn them at the beginning. You just need to know that these 8 fundamental strokes can vary.
With these 8 fundamental strokes and their variants, you can write about a hundred basic Chinese characters called graphic components. Some graphic components are words that we use like 马 mǎ (horse), others are never found alone like the water component: 氵 but only with other components. By combining these components, you can create an infinite number of Chinese characters. Learning graphic components may seem unnecessary or tedious for beginners, but it makes it much easier to memorize Chinese characters later.
Attention
You will often hear about "keys." The key of a Chinese character is the graphic component that allows it to be classified and found in a dictionary. Modern dictionaries list 214 keys. For the composition of Chinese characters, it is preferable to talk about graphic components rather than keys. Indeed, a Chinese character has only one key, but may be composed of several graphic components. Moreover, some important graphic components are not listed in the keys. Finally, many keys themselves are constructed with several graphic components.
Writing rules
A Chinese character is written in an imaginary square. If the character is composed of several keys, which is practically always the case, the keys should not be too far apart from each other, but should all fit in the same square; otherwise, they will be considered as different characters. Example: the character 好 is composed of two keys. If you don't write both in the same imaginary square, it becomes 女子.
When learning to write a Chinese character, you must strictly follow the decomposition, that is, the order and direction of the strokes.
There are seven essential rules for writing Chinese. You can consult them on this page The rules of Chinese writing. You must remember that vertical strokes are always written from top to bottom and horizontal strokes from left to right.
You learn to write Chinese on plain sheets of paper, such as printer paper. A ballpoint pen works very well for practicing. You write lines of characters in grids designed for this purpose. The site chine-culture.com offers a tool to generate writing grids for practicing. In this online Chinese course, you can download and print the writing grids for each lesson to practice.
The writing grids for this lesson as well as the example of a completed writing grid can be downloaded in the writing course for this sequence.