For the Green Planet project, I created digital assets by first downloading suitable vector graphics from freepik.com. I ensured that I added an attribution to this website on my portfolio page. 

I unzipped the vector graphics folder and opened the .eps file in Adobe Illustrator. Clicking on portions of the images allows the user to select individual vector components. Using this technique, I isolated portions of the graphics that I required for the project. I then resized the component and completed any finer touches like adjusting colors, resizing etc. Finally, I choose the Export-->Save for Web (Legacy) option to save the digital asset as a .png file. In this manner, I created all the assets I needed for the project, organized and saved them in a  folder for easy access.

This is a simple technique I used to create digital assets for an instructional design project.