@totalnoob - the file /etc/default/grub is one of the key files used by Linux to control how your computer boots up, using certain parameters.
If you open a Terminal and type in and paste the command (does not require sudo)
you can copy and paste the output to here. Best is to copy it to inside the Code Tags
The first three (lines (after comments, which are preceded by a hash) will likely look as follows
Code:
GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=10
... it is these that we can likely change, to provide you with a permanently showing grub menu at boot, and to further progress your wish to have Windows showing as a choice.
When that appears, move the arrow keys to move up or down, and the choice will remain until you select it.
Take a phone picture of the grub menu and post it up to us. See my article here
https://www.linux.org/threads/posting-screenshots-at-this-site-read-this-for-easy-way.21722/
for how to include pictures or screenshots.
Allow for my timezone to respond, I am on East Coast Australia (Queensland)
Wizard