You are free to use them as is or modify them to your liking. All i ask is you credit me if you do use them please :)
This is what’s known as an “informal license” and, in some countries, it puts people who take you up on that offer at legal risk.
My advice is to edit the metadata in the “More Information” box and set “Asset License” to one of the versions of the Creative Commons Attribution (CC-BY) license, which lays out “do whatever you want as long as you give me credit” in precise legal terms.