If your publication is listed as "In process" highlighted in blue, then there is nothing you need to do at the moment. Your paper has been submitted through the NIHMS system, and is being deposited into PMC. Once a paper has been submitted to the NIHMS system, it generally takes 4-6 weeks for it to be deposited into PubMed Central and shift to being marked as compliant and turning green. For grant renewal and reporting purposes, this is considered compliant.
However, it is highly recommended that you log in to the NIHMS system and track this publication periodically to ensure that no problems arise.