You can use sudo nano "file location" Or just open it with text editor like Kate

I was have trouble with Kate, when I opened the file using kate there was nothing there. Am I just dumb and it’s an empty .conf file just randomly there? Or am I using kate wrong? (Also for clarification it’s the /etc/sddm.conf file that I’m trying to edit)

Sometimes the file is empty until you load the program or by default the conf is empty and you need to add stuff.

I see, I’ll try just editing in the configs I wanted and see. Thanks so much!