Dual-Boot How-To Wanted

I'll preface this by saying I am no fan of dual-booting and a huge fan of virtualization. That being said, I was tasked with setting up a Dell tower as a Windows 10 / Linux dual boot. I haven't set up a dual-boot system in 15 years or so, and the steps have left my brain.

The Dell tower has some decent specs, but most importantly, it has one SSD currently. That is currently booting Windows 10. The plan is to add a second SSD for Linux. I don't believe it matters, but the end user is deciding between Ubuntu and Fedora. So, is there an easy way to add this second SSD, install Linux to it, and have it be available as a bootable option? I've installed Linux dozens of times, but always as a VM or a standalone, single OS.

If it were me, I would remove the Windows 10 SSD, install Linux to the second SSD by itself, install rEFInd boot loader on the Linux SSD:
The rEFInd Boot Manager

Reconnect the Windows 10 SSD, but keep the UEFI boot order booting from the Linux SSD first. rEFInd should see the Windows 10 automatically and add it to the boot menu.

Hi there.

If dual booting install Windows 10 first and then Linux -- the Linux boot manager can handle Windows boot manager and will prompt at boot whether you want W10 or Linux to boot.

If you do it the other way around i.e install Linux before Windows , Windows hoses up the Linux boot manager and it's possible in some circumstances the system won't boot at all. !!

It doesn't matter which drive each OS is installed on - the boot manager is the important bit -- whether UEFI or BIOS. The computer will read the boot manager from the default boot disc and the boot manager will pick the required OS from whatever HDD it's been installed on.

Note also you can install Linux on a 2nd partition i.e say "D" so you don't have to use 2 HDD's. Note of course that the boot manager will still be written to the UEFI / boot sector of the HDD and not the partition.

Cheers
jimbo