Welcome to the PowerSchool Community and the Unified Classroom Forum. Based upon your question, it sounds like you need to add links to the Class Pages section of Unified Classroom.
If you create a content block, and add the link to the content block, the link should automatically open in a new tab. However, if your browser has pop-up blocking enabled, you will want to ensure that you add Unified Classroom and PowerSchool Learning's domains to the white list.
For more information on setting up Content Blocks in PowerSchool Learning or Unified Classroom's Class Pages, you may look over this helpful article: