STEP 1 Go to http://developers.facebook.com, click LOGIN on the top right, and login with your Facebook account. (If you do not have a Facebook account, then click CREATE NEW ACCOUNT)
STEP 2 If you don't already have a Facebook account, create a new Facebook account. Follow the steps in the wizard to create a new Facebook account.
STEP 3 Click GET STARTED in the top right.
STEP 4 At the Welcome to Facebook Developers screen, click NEXT.
If you do not see any of the below screens, then click on the top right, click MY APPS and then click + ADD NEW APP.
STEP 6 Select 'OWNER/FOUNDER or whatever is most appropriate.
STEP 6.1 Click CREATE FIRST APP.
STEP 7 Under Display Name, type your APP NAME here. Specify an appropriate email and select CREATE APP ID.
STEP 8 At the Left Menu > click the '+' icon next to Products.
STEP 9 At the top where it says "Let people login with their Facebook account", click SET UP button of Facebook Login card.
STEP 10 On the left menu under PRODUCTS, click SETTINGS.
STEP 11 At the top and under Client OAuth Settings, make sure all the 7 buttons are toggled YES.
STEP 12 Click SAVE CHANGES in the bottom right.
STEP 13 On the left menu at the top under DASHBOARD, click SETTINGS > Select BASIC.
STEP 14 Copy the APP ID + APP SECRET for the next step.
STEP 15 Add your CONTACT EMAIL and this PRIVACY URL https://mystudio.app/MyStudio_Academy_Privacy_Statement.html
STEP 16 Click SAVE CHANGES in the bottom right.
STEP 17 Open a new tab in your browser and navigate to firebase.google.com > Click go to Console in the top right
STEP 17.1 Click on your project.
STEP 17.2 Go to Authentication > Sign in Method > Facebook and then copy the Valid OAuth Redirect URI as seen below.
STEP 18 Once you have your Valid OAuth Redirect URI, go back to http://developers.facebook.com > Under Products + Facebook Login, click SETTINGS > Paste your Valid OAuth Redirect URI in the box with that says Valid OAuth Redirect URI.
STEP 19 On the top right, ENABLE THE STATUS to production by switching on the button as show in the below screenshot. For Category SELECT BUSINESS AND PAGES.