1. Go to Sharepoint document library page 
  2. Example: https://leoadaly.sharepoint.com/sites/insite/life/LIFEHRConfDocs/Forms/AllItems.aspx 
  3. Choose the “Gear Icon”
  4. Choose “Site Contents”

  5. Choose “Recycle Bin”

  6. Select the file you wish to restore back to the document library
  7. Select “Restore”