Workflow doubt

[3ng3l64]

This is trying to do that when you receive an email, register that contact with the name and email. But I don't know how to make the condition so that I don't create a contact every time an email arrives. I want to know how I have to do so that I only create that contact if that email is not registered in any of the contacts and if it is registered that I link it to the contact with that same email thanks for the help i really love this project