TFT display

New to the forms, I have a tft hdmi display that is 800x420. I just want to display the home assistant terminal that you get on the hdmi display when you plug it in. I believe I need to just change the screen resolution. Where do I go to do that? I’m running it on a raspberry pi and I know you can change it on raspberry pi os under /boot/config.txt but I can’t find that file.