I did a lot of search but things looked very complex, I just cannot believe it will be such difficult. So I think some tutorial may be written long time ago and thing could already became easier. To be pretty clear what I should do, I have to raise this maybe duplicated question.
I am a Slackware user, had no experience in Ubuntu. I just got a new laptop installed with Windows 10. I then bought a new SSD disk for it and decided to install Ubuntu 18.10 onto this new disk and dual boot the laptop along with the existed Windows 10. The windows 10 is booted by EFI and I've already disabled 'fast boot' in Windows.
I dumped (dd) the Ubuntu 18.10 to an USB stick and booted it to execute the installation. I did not see any options like 'install alongside windows', so I choose to manually create partitions and told the installer the mount points. Of course, I did every thing on the new disk, did not change anything on the old disk that hosted Windows 10. Basically, I created three partitions, one for root, one for home and one as swap. The installation went so smooth and it can even detect the Internet connection. Just after a while, the installation completed. But the real problem I met is, there is not a new EFI boot option after reboot the laptop. Whatever I tried, it seemed like I've already installed the Ubuntu, but just cannot boot it.
What should I do? Some net tutorials said I have to erase everything and install Ubuntu first, this is not an option to me. I can erase the 2nd disk, but cannot damage the first disk, because this is my company's computer. IT department will not install Windows for me after the laptop has already installed a Linux.
Please someone help. Thanks. woody