With your Adobe Creative Cloud plan that brought by IU, you could access to a huge image database, Adobe Stock Image.
First, we must start with your limitations that you won't have guaranteed access to its "premium content", including all the videos, and "editorial only"-tagged images. Though you are not totally excluded, it takes a much longer time to request the license for a 20 second small video than you find a similar one on websites offering free short video resources.
But other than the limitation, you are free to use the rest of millions of images. The attribution format is easy, you just need to have the "author name - stock.adobe.com" for each of the image you use from Adobe Stock Image.
Once you find a image you would like to use, click to see if it is included in your plan, and then click the blue button. The image would be automatically downloaded and saved to your library. Remember to attribute the author (in red circle.)