Hello @Marijana_Petrovic,
We recently published this Google Scholar guide: Google Scholar Guide - I’d encourage you to have a look. While most of it relates to the OJS software, a lot will be relevant to OMP. Please note that there is an open issue with Google Scholar citation tags that we are still working on OMP: Google Scholar tags only appear on PDF view page, not on landing page · Issue #5686 · pkp/pkp-lib · GitHub - that may prevent your OMP contents from getting indexed.
For some context, please see the forum post here: How to make Google Scholar harvest the OMP metadata - #17 by Monica_Westin
Best regards,
Roger