First I have to say that I'm pretty new to Linux/Kali.
I just installed Windows 10 and Kali on my new SSD.
Windows 10 was installed first and then Kali.
The Laptop I use is a Samsung NP355V5C.
In the past I already had both operating systems installed on it, but it was on a 750GB HDD. Now I'm using a 240GB SSD.
And because I failed to clone my HDD onto the SSD I choose to make a clean install with Windows and Kali.
The Windows installation went smooth and the Kali installation too.
At the end of the Kali installation it said it installed GRUB successfully and I should now reboot the system.
I plugged the USB drive out started the Laptop and it started into Windows.
After that I shut it off, selected the SSD as the boot drive, but the it said I had to select a proper boot device.

I tried fixing GRUB with an Live Kali System, but when I suposedly mounted the system and type in "grub-install /dev/sda" it says: "no such file or directory exists".

I'm kinda lost here and I'am thankful for any help!