PW Installation
Go to your WordPress site’s plugin admin

Search for ‘Patreon’. Patreon WordPress will be listed

Click ‘Install Now’ to install PW

This process takes a few seconds. At the end, the plugin is inside the WP installation and ready to activate:

Click activate. You will be met with various welcome messages.

After this, visit your plugin settings at ‘Patreon Settings’ menu in your WP admin:

You will see the API settings window above. 

Open page at a new tab. This will open the Patreon’s page for client details for your account.

Click ‘Create Client’ if you didn’t create a client for this website before, and click to edit the relevant client if you have created one before.

If you havent created a client before, copy/paste the Redirect URI setting in the above section in your plugin settings to the relevant input box at the Patreon client screen.

If you have created a client before, just click Refresh at Patreon page to refresh the client tokens.

You will end up with a newly created or fresh set of client details.

All you need to do is to copy and paste each one of them from Patreon page to your plugin settings. When done, click to save the settings at your plugin settings page. This will save the client details. 

If successful, the plugin will inform you that it was able to successfully connect to Patreon. If anything failed, it will warn you that connection failed. In the second case, make sure if you copy/pasted your details from Patreon to your plugin settings correctly, and you did not copy/paste any spaces or other characters at the start or end. If you cant resolve your issue, post a thread at the official support forum.