Tags and Entities are both found in the Default Tray on Windows or in the Window menu on Mac.
Tags
Tags control the visibility of an object/entity. You can give multiple entities the same tag (i.e., “roof,” “outer walls, ” or “second floor”), and click the eye icon in the Tags tray to make everything with that tag invisible. This can make it easier to work inside of a model.
Entities
Each object in your model is an entity. The Entity Info tray gives you more information about each entity, like the square footage.