Backup external drive

I use an external hdd for data due to frequent carrying. Make backup manually once per 14 days on an other external storage. How can this be a way to relieve automatic incremental backups, so that data on both disks are up to date?
It operates some sw this style?:
1/ primary backup data to another disk
2/ after a certain time comparison of both disks
3/ update backup - only new or changed files (incremental backup)
I tried Beyond Compare, which is great for some users. Especially for someone who wants to have total control over the process. After all, it is more efficient for me to somehow automate= more simplify.
Thanks for the tip
Peter

 

Something like SyncBack Free would do the job. You can define as many backup jobs as you wish and set a schedule for each to run automatically. Each job - it's called a profile - keeps two sets of folders in sync.

The free version meets most users needs but there are paid versions too with more features.