Please be clear about what software you are using. Are you using Lightroom (Lr icon) or Lightroom Classic (LrC icon)? Please provide the version number and the operating system version number. We need numbers and not words like "latest" or "up-to-date"
You do not 'import' a backup. If you use Lightroom Classic and need to use a catalog backup because something is wrong with your current catalog, then you must replace the current catalog file by a backup copy (unzip the backup first).