"Ahead-of-print" allows you to submit the manuscript metadata (title, authors, abstract) to PubMed immediately, so that your accepted paper will be indexed in Pubmed within 24-48 hours after APF payment.
Please use the metadata preview link to see how your article will look like. Before paying / submitting the ahead-of-print version, make sure you update the abstract / title in the metadata form with the latest version, and check if all authors have been added.
To edit the metadata, click the "edit metadata" link.
The ahead-of-print abstract in PubMed will link to the Preprint page which shows the accepted paper.
Once the final version ("version of record") is published, the "ahead-of-print" abstract in Pubmed will be replaced with the final version.