Go to the NIHMS System home page, http://www.nihms.nih.gov/
Login using the same credentials that you use to login to eRA Commons and My NCBI. (Note: The NIH has made many changes to how we log in to things recently, if you are having issues either contact the library or the NIH Helpdesk directly)
Once you are finished with the submission, the manuscript will be put in the queue for conversion to its web version. You will be notified by email when the Web Proof is ready for review. Ensure that all emails regarding the submission are answered promptly to limit the delay in deposition to PMC
Note: The NIH Manuscript Submission Reference Number (NIHMSID) is a temporary identifier to be used only until the PubMed Central Reference Number (PMCID) has been assigned. For this reason, the NIHMSID becomes invalid 3 months after the paper is published. See this NIH Notice for more information.