I have a 2018 Macbook Pro and I am trying to dual boot Ubuntu. I have been following this guide: https://www.maketecheasier.com/install-dual-boot-ubuntu-mac/. I am using reFIND as my boot manager, and have partitioned my disk with a 200 GB MS-DOS FAT partition using disk utility. When I load Ubuntu via the USB and try to install Ubuntu, it cannot see the partition I have created and says there is not enough space to install Ubuntu (only sees the 4gb on my USB). How do I proceed? I've tried Ubuntu versions 16.04 and the latest 18.04 as well.