How to create asset bundle? Please, I'm lost :(

In an Custom Editor Window I made, I assign 2 Sprites:

Sprite spriteA = (Sprtie)EditorGUILayout.ObjectField("spriteA", spriteA, typeof(Sprite), allowSceneObjects: true);
Sprite spriteB= (Sprtie)EditorGUILayout.ObjectField("spriteB", spriteB, typeof(Sprite), allowSceneObjects: true);

now I want to store them in a new Assets Bundle I want to create in code (not manually).
How can I do it?

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