I have an SSD and an HDD. I've created separate partitions for Linux on the HDD (SWAP,boot and the storage), but I installed it on the the SSD on "Device for boot loader installation". I want to know what happened and skip the Linux Mint boot menu if it's not mandatory. Have I done something wrong in the installation?
You did it right. GRUB2, the aforementioned Linux Boot Loader, has Mint set to appear first, above Windows Boot Manager. It's the design of the program.
First, in the current GRUB2 menu, note the items which apear, and the line they are on.
In a terminal window, execute (you can substitute any text editor for nano, FYI)
sudo nano /etc/default/grub
and find the line with
GRUB2 starts counting from 0. you see. In the editor, replace 0 with the number of the line Windows Boot Manager is on (starting with 0 at the top) and save the file, then exit. Execute
which tells GRUB2 to accept the changes. The next time you reboot, Windows Boot Manager will be at the top of the GRUB2 list.
This does not alter the installation nor which drive you installed Linux to.