Typically the boot drives partition table holds the info on where the OS sits. Here you will want to create multiple partitions each one setup to support the given OS. Depending on your OS choices you’ll need to review the docs. As an example with MS-DOS you would run FDISK, with MS Windows 10 run Disk Management [https://support.microsoft.com/en-us/windows/create-and-format-a-hard-disk-partition-bbb8e185-1bda-ecd1-3465-c9728f7d7d2e|Create and format a hard disk partition]. You still need a means to jump around the different OS’s. Here’s a helpful guide [https://www.lenovo.com/us/en/glossary/what-is-dual-boot/?orgRef=https%253A%252F%252Fwww.google.com%252F&srsltid=AfmBOorPZgsnvdwBD-nHizmEp-vvWLK4xcID8xo6lAt4z6u2pd3ClD1Q|What is dual boot? With Windows and Linux]