In order to begin the Crossmark implementation, (1) one needs to create a policy page as seen at HePG CrossMark Policy | Plant Science Today and should be submit to CrossRef - HePG CrossMark Policy | Plant Science Today
(2) Then, DOI of an article should be submitted at CrossRef. It can be done either manually or through the CrossRef plugin of OJS.
(3) After that, add link at like “Crossmark” on your journal. I do it as a Galley item, so a link will be automatically generated while publishing the an article which will be placed next to your article PDF view/download link.
(4) Meantime, you need to submit an xml file manually at the CrossRef site (select Type = DOI Resources). See the XML file given below:
<?xml version="1.0" encoding="UTF-8"?>
<doi_batch version="4.3.6" xmlns="http://www.crossref.org/doi_resources_schema/4.3.6" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.crossref.org/doi_resources_schema/4.3.6 http://www.crossref.org/schemas/doi_resources4.3.6.xsd" xmlns:ai="http://www.crossref.org/AccessIndicators.xsd" xmlns:fr="https://www.crossref.org/fundref.xsd">
<head>
<doi_batch_id>101471901.8.3.1(can be any number of yoru choice)</doi_batch_id>
<depositor>
<depositor_name>Submitted Name goes here</depositor_name>
<email_address>emailidgoeshere@doamin.com</email_address>
</depositor>
</head>
<body>
<crossmark_data>
<!--the DOI being updated with Crossmark metadata-->
<doi>10.14719/pst.2021.8.3.1239</doi>
<!--Crossmark metadata-->
<crossmark>
<crossmark_version>1</crossmark_version>
<crossmark_policy>10.14719/CrossMarkPolicyHePG</crossmark_policy>
<crossmark_domains>
<crossmark_domain>
<domain>horizonepublishing.com</domain>
</crossmark_domain>
</crossmark_domains>
<crossmark_domain_exclusive>true</crossmark_domain_exclusive>
<custom_metadata>
<assertion name="crosschecked" label="CrossChecked">Yes</assertion>
<assertion name="peer_reviewed" label="Peer Reviewed">Yes</assertion>
<assertion name="published" label="Published">2021-07-01</assertion>
<assertion name="license" label="License" explanation="https://creativecommons.org/licenses/by/4.0">Creative Commons Attribution</assertion>
</custom_metadata>
</crossmark>
</crossmark_data>
</body>
</doi_batch>
You are done!