log in before accessing a page?

Hello guys! i am just starting to set up a local business directory. currently i have a home page and a business directory page. the directory is a plugin. the page has 3 buttons. add listing, view listing, search listing.

now, i want visitors first to sign up/log in before adding their business in the list to avoid unwelcome visitors spamming.

i am really new in web dev and i don’t have any idea where to start. i need 1.sign up page > 2. log in 3.add your business in the directory listing