changing localhost url

Im trying to add Multisite to my WordPress on a MAMP localhost. I changed the apache port to 80, added the define multisite code to the config file, added the proper imaginary url to the httpd file, and went into my terminal and added the imaginary url into my local environment there with sudo pico.

How do I now change my url in wordpress from localhost:8888/cnb_press to the imaginary url I created????????

I can’t find out how to do this anywhere.