During the sunrise of a new TLD, you may go to a Registrar to request the registration of a domain name (e.g. exampleone.example or example-one.example). The registration process is going to be similar to the process you are used to with your favorite Registrar, but at some point in the process, the Registrar will ask you for your SMD file. The Registrar may require you to upload the SMD file (similar to the process to upload an attachment on a web mail provider) or to copy/paste the contents of the SMD file (select all text, copy and paste) into a text box.