How to integrate OAuth2 into Bubble for Dwolla API

Hello, I am a developer and I would like the user to make a Dwolla transaction on my website.

I notice that (1).I need to the user to authenticate (OAuth2 protocol) through the Dwolla API first to obtain an authentication code.

(2) I would then use the authentication code to retrieve the access token.
(3) And then the user would be on their way to making a transaction.

The problem is, the Dwolla API isn’t integrated into the Bubble environment yet, unlike Facebook or LinkedIn for example, so I’m having trouble doing the setup in the API connector for (1).

I cannot even properly test this through the “preview” mode, because a redirect_url is required to go through the whole authentication process. This is what I have so far

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