How do I switch between OS?

[Pokem]

So, the yesterday I installed RemixOS. Pretty much an Android based OS. After that, I went into Control Panel, system and security, system, advanced system settings, and settings under the Startup and Recovery. I checked box Time to display list of operating system, restarted and it worked. Windows Boot Manager screen appeared.
Today however, it didn't go so well. I tried to boot into RemixOS through the same method, using CMD, etc. and no luck. It just booted straight into Windows 10. Anyone know a solution to this?
At least a way for me to enter the Windows Boot Manager screen again?

PS: I installed RemixOS on a separate partition.

 

[DeoNaught]

So, the yesterday I installed RemixOS. Pretty much an Android based OS. After that, I went into Control Panel, system and security, system, advanced system settings, and settings under the Startup and Recovery. I checked box Time to display list of operating system, restarted and it worked. Windows Boot Manager screen appeared.
Today however, it didn't go so well. I tried to boot into RemixOS through the same method, using CMD, etc. and no luck. It just booted straight into Windows 10. Anyone know a solution to this?
At least a way for me to enter the Windows Boot Manager screen again?

PS: I installed RemixOS on a separate partition.

So you didnt install another bootloader?

 

[Pokem]

So you didnt install another bootloader?

Don't even know what that is x.x

 

[Futurdreamz]

You might want to re-check the instructions you followed. If you don't know what's happening with your boot loader, nobody does. The boot loader is a bit of code that tells your computer where your OS is and how to run it, and depending on if you fucked up bad or not it could be anywhere. If your computer has EFI then that simplifies things, but instead of having us list every scenario it would be best for you to figure out what your system is set up as and what you did.

Key words for googling to get a better idea:
MBR
EFI
GUID
BIOS
dual-boot
partition
Windows 10 secure boot
GRUB

 

[Pokem]

You might want to re-check the instructions you followed. If you don't know what's happening with your boot loader, nobody does. The boot loader is a bit of code that tells your computer where your OS is and how to run it, and depending on if you fucked up bad or not it could be anywhere. If your computer has EFI then that simplifies things, but instead of having us list every scenario it would be best for you to figure out what your system is set up as and what you did.

Key words for googling to get a better idea:
MBR
EFI
GUID
BIOS
dual-boot
partition
Windows 10 secure boot
GRUB

Will look up some more for solutions.
but here's what I did so far: Went to disk management in control panel, shrunk C:drive by 32gb and made that my partition for Remix. I downloaded RemixOS from here: https://forum.xda-developers.com/remix/remix-os/remix-os-pc-hacked-edition-ota-v2-0-201-t3345968
it came with the tool, so I installed it.
This is the guide I followed:

At first, it worked completely fine. A screen that lets me choose between RemixOS and Windows 10 popped up and I was able to launch Remix. But a day after, I turned on my computer and that's gone. Made no changes. Just boot up, and it's gone. Not sure what I did wrong either. I installed it on my hardrive, so maybe that has something to do with it? I also have secure boot disabled. Dont know what EFI is, but I did saw something like UEFI somewhere.

 

[Pokem]

Installed EasyBCD because most solutions suggested it. Gonna see what it can do

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Hmmm, the installed OS is apparently missing files. Guess I should try redownloading the iso again

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also EasyBCD did say my computer is booting in EFI mode. Not sure whatever that means, but yeah

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gonna look more into this EFI and UEFI stuff

 

[Pokem]

ugh, since dual booting is such a pain, I'm just going to use a VM

 

[Futurdreamz]

It can be straightforward, but only if you know what's going on before you start. EFI is a new technology where everything is managed in your computer's firmware. Before it we used MBR, which was a special file located on the hard drive. It's possible RemixOS installed using MBR, which is possible due to backwards compatibility but not recommended. If everything was installed correctly using EFI then you should be able to switch between OSs by holding a key during startup - though you may have to enable the prompt timing because booting is so quick now.