The easiest way is to use [https://www.vmware.com/|VM Ware] . Create a virtual Machine inside windows . This doesnt require a second drive only about 20gb of free hard drive space. This is also great in that you dont have to shut down windows to boot into linux . I have four VM's on my machine to work across different platforms Ubuntu16.10 , Fedora Linux 26 , Yosemite, and an old version of windows XP. I can switch from platform to platform or run one on one screen and another on a second screen . You do need a lot of memory to run multiple OS's though . There are tons of tutorials on youtube to help with the setup and operation.
However if you dont want to do it this way and your patient . You can run different OS's from different drives . The easiest way is to install one OS then disconnect that hard drive and install another OS on another drive then connect both drives and when you boot your machine you 'll have to select in your boot menu which drive you boot from. You can also use a program called partition magic to create multiple partitions that are healthy boot partitions. Once again you can find tons of tutorials on youtube . The reason I said "patient"is that you need to shut down ever time you want to switch to a different platform . Anyway Padraic I hope this helps