After becoming a Tableplop patron you'll want to activate your benefits in Tableplop. That can be done on your account page.
On Tableplop.com:
Click the avatar in the top right of the page
Click "View Profile" in the menu
On your user page, under the "Tableplop Subscriptions" heading find the Patreon item and click the link titled "Connect your Patreon account".
Accept the link on the Patreon page that appears.
This will link your two accounts and Tableplop will automatically apply any benefits of your subscription to your account. If you make changes to your Patreon subscription the changes should be reflected on your account very quickly, you will need to refresh the page to see them.
Issues
If you see the error "You need to be logged in to do this" after linking your patreon account it is a bug. If you log in to Tableplop at the URL without the "www" linking your patreon will show "You need to be logged in to do this", I'm working on a fix but in the meantime use https://www.tableplop.com and try again.
If you experience any issues don't hesitate to contact me here on Patreon, on Discord (SummonToast#0001) or over email alex@tableplop.com and I'll get it sorted out as fast as I can.