Once you've found a project that interests you, click the 'Support Us' button on the project page.
Firstly, you will need to sign in to Projects for Nature or create a new account, if you do not already have one. Alternatively, if you do not wish to create an account, you can pledge using the ‘guest checkout’ option from a project.
For more information on donating funds, check out Crowdfunder’s Help Centre.