Re: [ANN] Zettelkasten - ZETTEL, coin with new hashalgo - CPU-mineable (for a while)
hi dev how to backup the wallet? 
You will find the "wallet.dat" file in C:\Users\%username%\AppData\Roaming\ZettelKasten. All you need do is copy this file and save is somewhere safe (AFAIK).
Another method is dumpprivkey and save them somewhere safe
how to do this
In the zettelkasten-qt app, go to the tools->debug console menu and once the console opens, type "dumprivkey " to get the private key of an address.