Download the Declaration of the authors.
Duly filled and signed by all co-authors the declaration has to be attached to the submitted manuscript. Please, fill in the template by computer (namely the e-mail addresses), sign the hardcopy and attached the declaration in pdf format to the e-mail together with the submitted manuscript.  

Don't forget to tick that you are aware of the Article Processing Charge and to answer questions on page 2. These requirements must not be avoided.