I'd like to install LineageOS on a CID 15 SM-G900V. I'm pretty new to all of this. I read about installing Lineage (using the instructions at https://wiki.lineageos.org/devices/klte/install) and found I needed to install TWRP, so I figured I'd try the dd install instructions at https://twrp.me/samsung/samsunggalaxys5qualcomm.html. I discovered su doesn't work because my phone's not rooted. Unfortunately, all of the instructions for rooting I can find are for Odin, but I'm running Gallium and macOS, so I'm using heimdall. I don't know how to translate from directions like https://www.androidinfotech.com/root-samsung-galaxy-s5-sm-g900v-verizon-marshmallow/ from Odin to heimdall.
In order to follow the root instructions, it looks like I need to flash the MD5 file. Am I right in guessing that the Bootloader, PDA, Phone, and CSC buttons in the Odin UI correspond to partitions? Which partition should I flash to? Or am I going about this all the wrong way?
I had tried towelroot, but it says my device isn't supported.