You can use CC-licensed materials as long as you follow the license conditions. One condition of all CC licenses is attribution.
Here is an example of an ideal attribution of a CC-licensed image:
This is an ideal attribution because it includes the:
- Title: “Furggelen afterglow”
- Author: “Lukas Schlagenhauf“—with a link to their profile page
- Source: “Furggelen afterglow“—with a link to the original photo on Flickr
- License: “CC BY-ND 2.0”—with a link to the license deed
How you attribute authors of the CC works will depend on whether you modify the content, if you create a derivative, if there are multiple sources, etc.