Changing the ul and li Image from default

I have been trying to locate the ul and li tags in my word press ‘archives’, ‘categories’, ‘recent comments’, and the ‘site admin’ option at the bottom of my blog. I’ve added the sidebar css tags with the img url that i want, but i still have the ‘black dot’ on the left of my image. can anyone guide me in the right direction?

the blog: https://blogsdominicanos.com/Edwin_Reyes/