identify the problem then remove it.
HOWEVER! Given the the amount of;
"I have no idea what I am doing"
questions you have asked, you probably cannot tell the difference between "blacklisted" and simply not good enough to even BE listed in search engine results.
So, ... What website are you talking about, ... And HOW do you know it is 'blacklisted'
Then follow up with the useful things you have done to market the pages of the website