From the "Details" section in the sidebar, you can find a few different actions for your assets.
"Delete" lets you delete an asset/project by moving it to trash bin or remove media which deletes media and mediainfo from asset while transforming the asset into a placeholder. Deleted assets go to the trash bin, from where they are permanently deleted automatically after 14 days if not restored.
"Copy" lets you create a duplicate of an asset inside the same or to another project.
"Move" lets you remove individual assets from the chosen project without deleting it entirely or move it to another project. Removed assets move to the "Upload" section, where all the unassigned assets are kept.