To upload your dissertation, you follow this link and create a new account at the ProQuest ETD site. Make sure you use the email you check frequently, since all of your correspondence regarding formatting revisions will go to the email address you use to register.
Once you confirm your new account by email, you'll be ready to upload. Below is a brief video which gives an overview of the upload steps.
Note: Alliant's policy (reaffirmed by the Provost's Council November 2015) is to not allow students to embargo their dissertations, because one of the main purposes of a dissertation is to contribute to the global community of scholars. If a student feels there are extraordinary circumstances necessitating an embargo, then the student must request an exception to this policy by contacting the dean who has oversight of the student's program.