“Provided that the content guidelines are met, the most common cause of indexing problems is incorrect extraction of bibliographic data by the automated parser software. To diagnose such issues, find a sample of included papers by searching Google Scholar for [site:example.com], go to page ten or later of the search results, and check if the titles and the authors of your papers are listed correctly. If you see very few results, and if their listed titles or authors are mostly incorrect, then chances are that this is, indeed, a parsing problem. E.g., if the name of your journal or repository is erroneously listed as the title of your papers, then there’s a good chance that many of your papers aren’t included at all, because documents with the same title are often considered duplicates.”
Google provides detailed guidelines for Google Scholar inclusion. If your papers are not appearing or showing up properly please refer to their troubleshooting section.