imagine you're building your house in minecraft, you want to show off a cool painting inside your house; but instead of making your own, you go into someone else’s house, grab their painting without permission, and hang it on your wall. every time someone visits your house, it loads the painting… from their chest. that’s hotlinking.
or in normal terms its basically directly linking to files from another website. it's a problem because the original site pays for the files being used every time someone opens it.
Oh, it's fine !