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Here’s one of the most useful resources to learn Unity and more specifically to learn to make 2D games in Unity. This should take you from a complete novice to a more experienced user in managing Unity in the 2D workflow.
Beginning 2D Game Development
Unity Learn is a great website to learn all-things Unity, from beginner concepts to the more advanced stuff, Unity Learn has it all. This particular course, Beginning 2D Game Development, teaches you all the basics, and even some more intermediate level stuff, so you can learn to make 2D games in Unity. This course has helped me quite substantially to make my game iFIX-IT.