If you want to clear your entire log area data and reimport, then you would use the REPLACE option on the Import Wizard. Be sure you create a backup before any import attempts so you can revert/restore to the prior checkpoint. Speaking of which, if you did not disable the backup option, it should have created a backup prior to importing, you can click File..Archive..Restore to restore back to the prior log data date and time.
If you need additional help, let me know.