Cannot open GParted GUI

Hi, I want to shrink my linux partition and by a couple of GB and give more to my Windows partition, and I can't seem to open the GUI with any settings under the USB version of GParted. And I do not know how to use the commandline version, and I'm too scared to mess with anything as I'm sort of a noob who just follows YouTube tutorials.
Could someone help me? This is what I get when trying to start GParted while booting from USB:
(I can't post 2 pics, but the first two lines were):

[sdb]No caching mode page found
[sdb]Assuming drive cache: write through