In the Project Management section under the Archives area you will see a green "+ Create Archives" button. Click the button and pop-up window will appear with a "Project Name" field and years to include in the archive. In the Project Name field you can name the project whatever you want, this is name that will appear in the list of archives so that you can access in the future. Hence naming your project Pay Equity 2015-2018, if you are making updates in 2019 that require archiving past years would probably be a good name. Select all the years you would like to include in the archive, generally you would include all the years and archive a project before making significant changes.
After naming and selecting years click the black "create" button and the archive will be created. You will receive an email after it is complete.
You can then access the archive in the Archives area of the Project Management section.