If you want to restore notes from the cloud:
Right click on the Notezilla icon, choose Sync and sign into your existing account. This will download all your notes that you have been syncing for last few years.
If you want to restore different notes than what are on the cloud then you can follow below steps:
Watch this short video that perfectly describes the feature:
(The video in above link assumes that you have access to Notezilla . However, if you don't then you can open the Notezilla data folder by opening the folder %appdata%\Conceptworld\Notezilla and follow the instructions given in the video. Copy this folder location and open it in Windows Explorer).
In short, you would open Notezilla data folder %appdata%\Conceptworld\Notezilla and also open the backup folder %appdata%\Conceptworld\Notezilla\Backup and copy Notes8.db file from backup folder to the data folder. Do all this when Notezilla is not running.
Notezilla keeps 5 backups. If you cannot restore the previous day's backup, then try a little older one.