How do I prevent this from happening again? I was told i need to make 2 copies/folders when i import in .... How do I do this?
Don't delete or remove the original photos from Lightroom, don't delete or remove the originals from your operating system.
And if you have deleted the originals and you do have a backup of these photos, as suggested above, use the backup instead of the export.
By the way, I consider the idea of making a 2nd copy TO A DIFFERENT HARD DISK at import optional, but if you don't do that, then you MUST make regular and automated backups of your photos to a different hard disk. In either case, you must also make regular and automated backups of your catalog file to a different hard disk.