I just got a Lenovo Thinkpad X1 Gen 6, I am trying to dual boot it with Ubuntu Mate 18.04. I partitioned my drive while in windows, also disabled secure boot. Although when I boot into Ubuntu Mate from the flash drive to install it, I only have the option to erase and install ubuntu mate. I watched a video that showed that there should be an option to install along side windows 10 but I do not have that option. I also tried installing it "some other way" (I think that was the option) where it listed the different partitions to install although when I tried to install on the one that I wanted it on, it said there was no root directory.
Thank you Please let me know if you need more information.