It seems that there are many ways and many different tools that can be used to configure a Windows 10 laptop/desktop to dual boot Ubuntu. I actually got things working on my XPS 15 notebook a while back … but I get weird errors periodically and don’t recall the steps I followed.
So …
For those of you who have done this successfully, what tool/steps did you follow?
I just installed from USB and followed the prompts. The only slight wrinkle was I first had to use Windows’ disk partition application to shrink my partition, and I also had to turn off bitlocker (so that Linux could mount my drive). Oh and I had to turn off ‘fast start’ in Windows for the same reason.
Once I did that, everything just worked 
Did you follow any steps in particular?
I’m looking at: https://www.tecmint.com/install-ubuntu-16-04-alongside-with-windows-10-or-8-in-dual-boot/
But for some reason, maybe scotch, I seem to remember it being much more straight-forward.
No I didn’t - I just popped the USB key in and rebooted, using BIOS to boot from USB. There was nothing I had to do on the ubuntu side to make it work.
You’re lucky. I bricked my machine trying to install Linux Mint 18.2. Btw, I’ve successfully installed that OS on countless older machines in the past but my new one, with its UEFI or whatever boot system doesn’t seem to like Linux and now refuses to boot into Windows. I’m typing this from Linux as of now while I download the Windows ISO to rescue my system.
if you have 2 separate drives, i would recommend keeping things separate. here is what i did, but with ubuntu 16.04:
http://linuxbsdos.com/2015/10/31/how-to-dual-boot-windows-10-and-ubuntu-15-10-on-two-hard-drives/
Secure Boot (and sometimes related settings like Fast Boot) needs to be disabled. Ubuntu 16.04 installation process is fairly well tested but I had to add nomodeset to the default Grub entry due to blank screen issue with Nvidia drivers (https://askubuntu.com/questions/760374/ubuntu-16-04-nvidia-driver-blank-screen). I actually had more problems installing Windows 7 on the same machine, since the Windows 7 installer does not work well on full UEFI hardware, so it had to be installed to MBR then converted to GPT later (a second/spare hard disk comes in really handy here if you don’t want to mess up an existing GPT disk).
The Ubuntu live installation cd has its own disk partitioning tool (gparted) which comes with more advanced options for people who are familiar with disk partitioning, especially for both Windows and Linux.
Having the Windows installation cds is a good idea in case you need to restore the boot partition/entries for Windows. Both Windows and Linux installations would usually share the same EFI partition, with separate entries to boot into Windows Boot Manager or Grub (Linux’s boot manager), but Windows media is still needed to recover the Windows side of things.
I did this and it was awesome for a while but eventually my NVidia drivers started giving me trouble so I gave up on it (not saying it’s not worth trying to figure out). Just wanted to share an opinion:
I’m currently using the Windows Subsystem for Linux and running Ubuntu. Its not perfect either, but its great for SSHing out to a machine on the cloud instead of using Putty. I’m hoping that it will continue to improve and be a viable option for using linux and windows together. I have to say its pretty neat!
To keep things up to date, I abandoned the dual boot setup. I left all the big hardware in the box to run Ubuntu 18.04 and just remote into it with Win10 Putty/VS Code. Its a much more reliable setup for me.