Dietpi Autostart problems

Hello guys
I just installed Dietpi latest version To my Raspberry pi 3 model b
I need help in two things
Im using tv hdmi running in 600*480 res I did some changes in Autostart I set it to 2 To have a Desktop and rebooted the os
Now nothing is displaying in my TV
It boots up normally But no display in TV please I want to know how to revert this changes I made ,disabling autostart
There’s nothing I can do while booting since no display is there anything I can do in sdcard

  1. How to run heedlessly I want to connect it to my laptop and run it through a ssh client or remote login (Putty)
    I tried from watching some videos, no luck a detailed explanation is appreciated
    Thank yoy