Dual booting with Windows 10 does't find Leap 15

Hi all,
I’m trying to make a dual boot Windows 10 x64 and Leap 15. For installing opensuse Leap I used KDE Live image on a USB stick. After install finishes and pc reboots I end up booting Windows 10 with no signs of other installed OS. What am I doing wrong, please help?

You must install so that ALL OS boot the same way ie one booting legacy and one booting EFI does not work. Also some hardware insist on only booting Windows. Assuming Windows is EFI boot then you must boot the installer in EFI mode not legacy. In any case you should be able to use the UEFI boot menu on your machine to boot to any installed OS. If not then you may have a hardware UEFI issue.

I tried to boot manually from F8 boot menu, but there wasn’t opensuse to boot in. Also, I don’t know in what mode I’m booting - EFI or Legacy. How can I find out?

Boot your live media.

Then post the output from:

sudo parted -l

Please

lsbkl -l

and

efibootmgr -v

LOL. I really messed that up.

So now I am on the liveCD and the outputs of the commands are:

linux@localhost:~> sudo parted -l

We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

    #1) Respect the privacy of others.
    #2) Think before you type.
    #3) With great power comes great responsibility.

Model: ATA ST8000VX0022-2EJ (scsi)
Disk /dev/sda: 8002GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name                          Flags
 1      17.4kB  16.8MB  16.8MB               Microsoft reserved partition  msftres
 2      16.8MB  7980GB  7980GB  ntfs         Basic data partition          msftdata


Model: ASMT 2115 (scsi)
Disk /dev/sdb: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number  Start   End    Size   File system  Name                  Flags
 1      1049kB  475GB  475GB  ntfs         Basic data partition  msftdata
 2      488GB   987GB  499GB  ntfs         Basic data partition  msftdata                 
                                                                                               
                                                                                                  
Model: SanDisk Ultra (scsi)                                                                          
Disk /dev/sdc: 15.6GB                                                                                    
Sector size (logical/physical): 512B/512B                                                                     
Partition Table: msdos                                                                                        
Disk Flags:                                                                                                        
                                                                                                                       
Number  Start   End     Size    Type     File system  Flags                                                            
 1      1049kB  15.6GB  15.6GB  primary  fat32        boot, lba, type=0c                                                      
                                                                                                                                     
                                                                                                                                     
Model: NVMe Device (nvme)                                                                                                                  
Disk /dev/nvme0n1: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End    Size    File system  Name                          Flags
 1      1049kB  524MB  523MB   ntfs         Basic data partition          hidden, diag
 2      524MB   628MB  104MB   fat32        EFI system partition          boot, esp
 3      628MB   645MB  16.8MB               Microsoft reserved partition  msftres, legacy_boot
 4      645MB   479GB  478GB   ntfs         Basic data partition          msftdata


linux@localhost:~> 

linux@localhost:~> lsbkl -l
If 'lsbkl' is not a typo you can use command-not-found to lookup the package that contains it, like this:
    cnf lsbkl
linux@localhost:~> efibootmgr -v
Absolute path to 'efibootmgr' is '/usr/sbin/efibootmgr', so running it may require superuser privileges (eg. root).
linux@localhost:~> sudo efibootmgr -v
EFI variables are not supported on this system.
linux@localhost:~> 

Looking at your output, I can see:

Windows is installed for UEFI booting, with the EFI partition on your SSD (NVMe device).

I am not seeing any evidence that you actually installed openSUSE. Your output does not seem to show any linux file systems.

You booted the live system in legacy mode, not in UEFI mode. Best to boot it in UEFI mode, if you can work out how to do that. Legacy and UEFI do not mix.

And that bad command: it was supposed to be “lsblk”, but the person who suggested it made a typo. But never mind for now.

Sorry.
With sudo. Or when you are log in as root (su -).

Well, the console outputs were made from the live system. Previously I logged in Windows and used Easeus Partition manager to delete all opensuse partitions in order to start over clean. So, how can I boot the live system in UEFI mode? In Youtube I saw a video where the guy mounted the windows uefi partition at /boot/efi and then booted correctly windows 8 and leap 15. Is that correct?

Here is the video

https://www.youtube.com/watch?v=GFbcXbNQDwc&pbjreload=10

look 3:50 min

Insert the usb key with openSUSE.
Boot with F8 or another another key (Fx). For me is F8.
Choose to boot from usb key who starts with uefi (efi).
Install openSUSE - /boot/efi in the same partition with Windows (your EFI system partition) WITHOUT format it.
You don’t need a legacy boot if you have UEFI.

When I open the F8 boot menu I get constantly an nouveau error when booting on uefi. Here is an image of the error

https://imgur.com/a/dmaGENV

Never mind if I installed from the DVD image or from the KDE image.