Hi there and welcome
Do you have a windows computer that is already connected to the wifi network?
Please let me know
To get the password ***** the Mac, please do the following
Step 1: Type Keychain Access into Spotlight search () at the top-right menu bar.
Step 2: In the sidebar, make sure you click on Passwords, then search for the network you want the password ***** and double click on it.
Step 3: Click on Show Password. Confirm your administrator username and password.
Step 4: You may be prompted to enter your administrator name and password *****
Step 5: The Wi-Fi password ***** appear in the text box next to Show Password.
Let me know how you go please