First click new and enter the following settings:
I named it OSX 10.9, and chose Mac OSX and Mac OS X 10.9 Mavericks (64 bit). Chose the appropriate one for you. Click Next.
Give it a certain amount of RAM. I advise at least 2500 for OSX but don't go above half your available memory.
The following settings should all be default:
First chose Create a Hard Drive now.
Chose the top one.
Chose dynamically and then chose at least 10GB (I went for 15. You need a lot for Xcode - 30+).
Click create.
Click settings.
Click System
Untick all but CD/DVD and then move it to the top with the arrow keys.
Untick Enable EFI (special OSes only).
Click Display, and give it 16MB Video Memory (if you can). It has to be at least 8.
Click storage and then the Plus CD icon.
Click Chose disk.
Navigate to your OS X .iso file. It needs to be Hackintosh. I got mine from here. You have to disable adblock to get to it. (I used a torrent so it downloaded quicker - it is 5.5GB)
It is legal, but against what apple like you to do (as Mavericks is now free you don't need to pay anything. You can purchase an OSX 10.8 licence if you want, to make sure you are covered).
Click Open.
Click OK.
Click start and you can boot it.
Press Enter, and follow the installation process.
Complete the installation process. Then go back to Settings -> System -> Boot order, and disable CD/DVD and enable Hard Drive and move it to the top.
It will boot correctly. Finally, open the app store and install XCode from it (it's free).
My pronouns are He / Him
Select a virtual machine by clicking its name in the VirtualBox window
Click the Machine menu at the top of the VirtualBox window, and click Settings
Click the Storage category in the Settings window
Right-click in the storage tree pane, and click Add Floppy Controller
Right-click the Floppy Controller device, and click Add Floppy Device
Click the Choose Disk button in the prompt window that appears
Navigate to the floppy disk image file (.IMG) on your computer and double-click it
If that doesn't work, try renaming the .IMG as .ISO and mount it.
If that too doesn't work, use VBoxManage's convertfromraw command as follows:
VBoxManage convertfromraw --format VDI [filename].img [filename].vdi
Finally, mount the VDI as a hard disk.
Best Answer
Sorry, Virtualbox does not support hardware emulation of the ARM architecture. You may want to look at qemu instead, which does support software emulation (slow, but works).