The steps are the same for W8. I would recommend W8.1. Burn your ISO installer to a USB. Power down your Mac, poor it up and use Alt/Option and choose the USB installer. When prompted for the destination partition, point it to the Free Space part.
I have the EFI setup on my son's Late 2013 15-in rMBP. Here is the disk layout. GPT4 is MSR and GPT5 is MS Data.
gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060
gpt show: /dev/disk0: PMBR at sector 0
gpt show: /dev/disk0: Pri GPT at sector 1
gpt show: /dev/disk0: Sec GPT at sector 977105059
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 487712920 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
488122560 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
489392096 32
489392128 262144 4 GPT part - E3C9E316-0B5C-4DB8-817D-F92DF00215AE
489654272 487450624 5 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
977104896 131
977105027 32 Sec GPT table
977105059 1 Sec GPT header
sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]
Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: EE 1023 254 63 - 1023 254 63 [ 1 - 977105059] <Unknown ID>
2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused