Windows 10 Set As Default Boot (Dual Boot)

I recently installed Zorin OS 15 Core on my HP TPN-C125 laptop. I figured that I had to come back to it since 12.3 and see what was new about it. Unfortunately, I cannot even run it without first running Windows 10, selecting advance restart, and then selecting the hard drive for Zorin to run. I also noticed that Zorin OS does not seem to have a grub menu. At least, that I am aware of because of my cracked screen. I have to rely on an external monitor for this one, so BIOS is not possible and unplugging the main monitor from the laptop is out of the question. What I do know is that Windows 10 is missing from the grub menu in Grub Customization. When I installed Zorin, I was not given an option to run it alongside Windows. In fact, Windows was being stingy on letting me run the USB in the first place despite me setting my USB as my default boot drive before the screen got cracked. I had to run the advance restart to do it. I am unsure of what to do now. How do I set Zorin as the default OS and let Windows 10 be an option in the boot menu?

Hi, it's unfortunate you have a cracked screen as you need to go into BIOS and turn off fast boot and if present, also Windows Boot Manager. Inside Windows 10 itself you need to go into Power settings and unhide the advanced options to turn off hard drive sleep mode which is effectively what Windows 10 does to increase speed of boot, not just fast boot. Zorin does indeed have a GRUB and usually shows if more than one OS is present. If it does not show then you need to hold down the left shift key during boot up to reveal GRUB menu. I would also install it using the Matthew Moore nonconventional method of dual booting:

https://www.youtube.com/watch?v=xlTgaWs9BD0