JBOD won't work. Help with LVM?

Hey guys. I tried creating 2 partitions on both a HDD and an SSD. I want the fast boot times, but I want all the User files and applications to be stored on a HDD as I only have a 120GB SSD and I want to put Windows 10 on it as well. Anyway, I took one partition from each drive and created a JBOD (RAID?) system 2 times. One for windows 10 one for macOS. This, however, would not allow me to install macOS onto the drive. I have done a little research and found that I can just use LVM (Local Volume Manager) which only would use the HDD once I am out of space on the macOS or Windows 10 partition on the SSD. Does anyone know how to set this up?

Why are you bothering with JBOD? Install Mac OS and Win10 on the SSD. Then use Linux2Mac's procedure to move user files to the HDD. Create User files on the HDD for Win10 and link them to the Library icons on the Win10 file explorer page. Set your Win10 apps to default save to the folders on the HDD.