An equation in slope intercept form is written as y=mx+b
m is the slope of the line
b is the y intercept or the point which the line crosses the y-axis
so as long you have the m and the b of the equation you can graph it.
for example say you were given the equation y=3x+7
plot a point at (0,7) as your y-intercept because b=7
then from that point go up the line 3 units and over one and plot a point. the slope was 3, so that's up three over 1 (only go over one because 3 is the same as 3/1. the numerator tells you how many units to go up. the denominator tells you how many to go down.)
so continue going up three over one until you have enough points to draw your line.
I hope this helped!!