https://www.domestika.org/en/courses/387-introduction-to-adobe-photoshop

Learn to master Adobe Photoshop, the most widely used tool for image processing and digital retouching

By taking these 5 courses, you'll learn to use Adobe Photoshop even if you've never used the program before. Through a series of practical lessons, you'll learn everything you need to know to become a design or digital publishing professional.  You'll start by getting to know Adobe Photoshop's interface and its main tools. You'll learn to manage and combine documents, work with layers and selections. Plus, another thing that's essential for this type of project: masks.  Then you'll dive into the world of photomontage and learn image size and resolution fundamentals. Also, you'll learn to use transformations so that you can portray anything that you set your mind to.  Later, you'll discover the vast world of options that Photoshop brushes offer.  You'll also learn how to use the retouching tools to reconstruct, clean up and improve your photographs and images with an impeccable and realistic finish.  Finally, Carles will explain how to properly apply adjustment layers. Using these, you can do a detailed light and shadow treatment and adjust the color to your project's needs.