You can send a message to a project owner directly from their project page. Click the option to 'Contact project', as shown in the example below.
If you're not already signed in to your Crowdfunder account, you'll be asked to do so at this stage. If you don't yet have a Crowdfunder account, you'll need to create one in order to contact a project owner.
Once you have signed in, you'll see a box appear for you to write your message. When you have finished your message and clicked 'Send message', it will be sent directly to the project owner via email.