perpetualflow on "Error establishing a database connection"

Hello,
I know this has been written about many times but none of the solutions I've come across fixes this problem.
I am on a mac and have downloaded MAMP as well as I have downloaded wordpress and put folder in 'default' htdocs folder. I have edited the wp-config file so that I have my new database name (I named it wordpress) with username and passwords as 'root'. I renamed the file wp-config.php. All spelling is correct. I am using apache port 80 and MySQL 3306 currently, although changing them to the default values of 8888 and 8889 does not solve the problem.
I am using the hosting site BlueHost and currently have a website (of 1 day) with wordpress.com. I am attempting to switch to wordpress.org. When I get to the step of going to localhost/wordpress, I come up with ERROR Establishing a Database Connection. I typed 'localhost' and it came up with wordpress/ on the screen below but once I click on wordpress/ I get the error. I have tried every variation on localhost to make this work, including localhost:80/wordpress.
I know with GoDaddy I might have to check that wordpress.com is pointing at GoDaddy, but it is the same if I'm using BlueHost? I'm at a total loss.
My webiste is perpetualflow.com.
Please let me know if there is any other information you may need.
Thank you so much for your help.