positive 4 is your y-intercept so you graph the dot on the y-axis.
For your slope, you have -x and one thing to remember with variables is there's always a invisible 1 in front of your variable so instead of it being -x it's also -1x.
With slope you do rise over run. so you go down 1 (because it's a negative) and the 1 (because the x is now positive)
the website i used is desmos, it's extremely easy to use.
i hope this helped!
