This gist describes how to create a component that will embed Oxi Social Login iframe. That iframe will display social login buttons. Clicking those buttons will open a popup where after a user has logged in to the provider, they will be redirected to the Shopify account page.
Add the Oxi Social Login App to your Shopify store. After setting it up in your dashboard go to the apps settings page. Toggle the switch for "Automatic Installation". Configure which providers you want to display. Finally enable multipass by adding your store's multipass secret. Directions for setting up multipass and getting the secret in the Shopify dashboard are here.