I have SSD and HDD on my computer, I installed ubuntu along side Windows 10 on the SSD, but when i turn on my computer Windows 10 was loaded without GRUB showing. I followed the order in this video: https://m.youtube.com/watch?v=F4fPwUFTwlk and now Windows Boot Manager is loaded, but the only option is load Windows 10. How can I make the GRUB menu appear?
You have to change the boot order in bios settings. Make Ubuntu boot first in os boot manager as for hp machines, then it will show GRUB menu.
Reboot your PC and press Esc or F10,F1 to boot loder. (As you mentioned its HP Lap)
Once you got the boot setting, Set ubuntu as default.
As know Esc will set temporary session for boot. Means if you load it again it will load windows.