NEW Developer, how do I upload a build?

Hi everyone, I'm a new developer. I'm uploading my SaaS network...think Netflix and I'm almost at the end and ready to submit, but the submit button is grayed out and when I hover over it is says, my first submission needs to have a binary attached!!

what is a binary and how do I get one?

How Do I upload a build?

How Do I sign my app?

Can someone help me?