It's well explained but I don't really get the last part
VERY IMPORTANT TO NOTE... that if you are using MULTIPLE Canva images to make a collage - it is important to provide the source of ALL images that went into your final image! So be sure to keep track of all those sources and cite them all! Of course if you're using other cc0 license sites like Pixabay, Pexels, Unsplash or more - simply use the URLs from there
some people will create an image by mixing multiple images together - to create a sort of collage
if you do that - then you need to say where you got the images from :)
Okay, I understand now