Add new entry in Grub Customizer for SSD Windows

I have 3 OS installed on my computer.

1. Ubuntu
2. Windows 10
3. Windows 8

Somehow after the Windows 10 update got stuck and I restarted the PC in between the update process, which I think corrupted the Boot Grub file.

Now I am only getting option to Boot either in Ubuntu or Windows 8 (Windows 10 option is not coming).

But I think if I add that in the Grub Customizer sequence, it will again show me to boot from that partition of my computer disk.

However I am unsure how to add the new entry.

Below is the Disk Structure showing in my Ubuntu:

The current Grub Customizer Windows Entry of Windows 8 (which is on the HDD /dev/sdb5) :

I want to add new entry for Windows 10, which is on the SSD - /dev/sda2

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.