I received a message that the destination path is not valid although I mapped the folder in the server and copied the bath exactly, please help
You cannot use mapped drives, because the drive mapping applies to you user only. SQL Server runs under a different user and does not see that mapping. You need to specify a UNC path like \\SERVER\Share\folder\db.mdf. However, putting database on network drives is not to recommend.
If you want to move the database to an instance on the physical server, BACKUP/RESTORE is the way to go. And again, you need to use a UNC path.