Look for options to search by Creative Commons license type. This may or may not appear on the initial search screen. Flickr, for example, has a separate page for searching or browsing by license type:
Look for options filter or sort by Creative Commons license type in your results list. Vimeo, for example, lets you filter by license type in the results screen:
When you find content of interest, look for details about the license. These details are often located near the creator and title information. You may see a license icon or the name of the license. One or both may be linked. Select the link(s) to get guidance in plain English on how you can use the content.