Help. 2 macOS versions on one disk

Hi. I have a catalina with the APFS file system, and I decided to try installing OS X Yosemite as well. I created a flash drive, created a partition on the disk with the mac OS Extended file system, I boot up, and the installation stops when there is 1 second left before restarting, and after ~15 minutes the computer shuts down, and there is no Yosemite. Can you tell me how I can fit these two systems on the same disk? Thanks