Hi Gaurav,
There are two approaches how to achieve the regular backup:
1. You could backup the database and the project folder.
2. You could create a custom scheduled task which would export the site.
This article from Developer’s Guide advices how to create a custom scheduled task:
Scheduling a custom codeAnd here is sample of programmatically site export by our API:
Import and export of a web siteBest regards,
Michal Legen