Error trying to connect stripe account for users

Hi!, I think that I have everything done in the back end. Now i´ts time to connect a creator´s project account, in the front end. I go to funding details, click on: connect with stripe, I login with a secondary account and I get it:

Congrats, you’re almost done setting up your application!
After connecting with Stripe, your users will be redirected to a page of your choosing (this is just the default). Make sure to change the test redirect URI under your application settings to something that makes sense on your own server.
To finish the process of getting an access_token for your user’s account, you’ll need to make one extra API request with the authorization code we passed back. In this case, the code is ac_GySp————R0mVdBE9nlovB, taken directly from the GET parameters on the redirect.
For example, try this curl request. Note that you’ll need to replace YOUR_SECRET_KEY with the application owner’s test secret key.
curl -X POST https://connect.stripe.com/oauth/token \
-d client_secret=YOUR_SECRET_KEY \
-d code=aac_GySp————R0mVdBE9nlovB \
-d grant_type=authorization_code
You’ll need to do this programmatically (we recommend some kind of third-party OAuth 2.0 library) — check out our OAuth tutorial for a more in-depth explanation! Or, head back to our getting started guide to get a sense of what what you’ll be able to do after your users connect with Stripe.

What I have to do now?
One more thing, If Me, like webadmin, with my stripe data in the Funding Settings at the back end, would like to create a project, how can i do it? how can i collect funds?