If you've created a fundraising page at Wonderful.org there's no need to do anything in order to 'release' the money you've raised and get it sent to your chosen charity.
When donors make donations on your fundraising page, the payment they make is transferred instantly and securely from the donor's bank account to the charity's. That means as you fundraise, your charity receives the money you've raised in real-time, which can be especially helpful for charities providing emergency aid, for example.
Your chosen charity is able to access detailed reports of the donations made to them through their Wonderful account. They should liaise with the Wonderful support team directly for assistance with this.
If you're still unsure or need clarification on any of the above, you can contact the Wonderful support team.