It's not really complex, but sometimes windows will overwrite some part in the EFI Partition and Mac won't start afterwards.
If you use two separate drives it is just easier.
To make Dual Boot happen you need to first format the drive as HFS+ using Disk Utility from Mac.
There you add a second partition which has to use MS_DOS.
Then you boot the Windows installer (You have to boot the installer in UEFI Mode, otherwise it won't work).
In the Windows Installer you have to find the MS_DOS Partition, delete it, and use the new available free space to create a new partition.
Then install windows on this partition.
After you have done this you install Mac on the fist partition, install clover and you should be done.
When your System is working you have to always switch from Mainboard Port to Graphics Card Port and back, when you want to boot Mac or Windows.