Protecting the private key is indeed very important.
Generate it, store it safely and have backups.
If you're not sure how to do this or have found a good resource explaining how to do it feel free to comment here.
I can tell the keys have been stolen
my address 1DoNATeVUFvfgwmZLr6CHBXgQFus5sVnsS
transaction in which other addresses have been emptied with the specials name f2d3adfd0296b94a44a7ac69a11d9146b4998df75daee96fa29095394df3dcf5
There was one payment transfer since the address was generated. The key was never used and kept in a locked safe. After four years the funds disappeared stolen