The Stripe Setup page can be accessed by going to the "Options" button from your main dashboard page. Click on "Account Settings":
And then by clicking on "Stripe Setup":
Once on the page you will see the following:
To find your Stripe keys please check out this Stripe article: https://support.stripe.com/questions/locate-api-keys-in-the-dashboard
You can use your TEST keys or your LIVE keys with Project.co. We'd recommend using your TEST keys first to make sure everything works as expected.
To do this, enter your test keys and save. Then set up a payment on a test project and choose "Make Payment" from the options button on the payments page. Then test the payments process using the Stripe test card details from here: https://stripe.com/docs/testing
When you're happy that the process is working well you can switch from your TEST keys to your LIVE keys and take live payments on your projects.