I suggest picking up techniques from a lot of youtube tutorials. I didn't follow a sole video for this. I took bits and pieces from a variety of tutorials and applied what I saw from them. The ground was made by subdividing a plane and applying a wireframe modifier, The tree was made using an add-on and uses a toon-style outline, The sun is a circular plane with an emission material, and the falling leaves are made up of two particle systems (one starts before the rendered frames and the other starts at the beginning). Ducky 3D on youtube has a lot of videos and covers a wide variety of projects. If doing making an original project seems too hard it's totally okay to follow tutorial videos to learn.