Plutonium is its own app, it's not a software like the other you could download.
You have two solutions
First solution: if you want to download it to another drive you can either create a symbolic link which basically makes Windows think it's on C: (so that nothing breaks) while actually storing the files on D: for example
This example should guide you https://plutonium.pw/docs/modding/moving-to-another-drive/
Second solution: if you really want to install Plutonium on another drive I think you could use something like this in a bat file. Just make sure this bat file is in the same folder as plutonium.exe
@echo off set installDir=D:\Plutonium plutonium.exe -install-dir "%installDir%"