Note: Computer is MBP17 Late 2011 running OS X 10.11.4 & Boot Camp Windows 10, the later I intend to erase.
You intend to erase W10 and install Linux in its place?
If yes, I would use the Bootcamp utility to erase Windows and reclaim the space.
Then use the Disk Utility to create a new partition as MS-DOS FAT (lets say 50GB) for your Linux install. Make a bootable USB with the Linux distro of your choice (I use Unetbootin to create bootable usb).
Reboot your Mac and hold down Option key after you hear the chime. I think you should see 3 or 4 options. One is Yosemite, then recovery if you have it, the next one should say Windows (Mac thinks it's Windows because it's FAT32), and last will be EFI. I prefer to install Linux in UEFI so I would choose the EFI boot option.
Boot into Linux, start the installation process. You will be asked where to install it. For some reason for me Linux Ubuntu or Mint were never able to see OS X so they asked if i wanted to erase disk and Install Linux. I chose the "something else" option. There you should see all the partitions of your hard drive. Remember which one is the one you made for Linux (lets say the last partition with 50GB space).
You need to create a "/" partition which is a root partition or otherwise you won't be able to advance. You can create additional 'home' partition if you would like too but it is not necessary.
After you create the root partition, select it and hit continue. Installation process begins and it only takes a few minutes.
After installation is done and computer re-boots, you won't be able to see the new Linux install. You either have to modify some boot file in OS X (which I never messed with) or install a bootloader like rEFInd while in OS X.
http://www.rodsbooks.com/refind/installing.html