boot – Ubuntu installer crashes on Installation Type screen

im trying to install ubuntu 20.04.1 lTS on my lenovo 720 13ikb laptop. I am currently able to live boot from USB, bbut when I get to the installation type screen in the installer, no options show up, and clicking the plus, minus, or change buttons causes it to crash. does anyone know how to fix this? thanks so much
extra maybe relevant info –
iin order to eeveeven live boot Linux i had to change the SATA type from RAID to AHCI. this has made Windows currently unusable, which wasn’t going to be a problem since I want to only use Linux.

edit: when I click install now without selecting anything, the dialogue box says “no root file system is defined”. i dont know if this is normal or not, but thought it might help