Hey there! I'm happy to help!
The y-intercept is where the line runs into the y-axis. Because of this, you can immediately put a point on the 3 on the y-axis.
Then, for the slope, this is the rise/run. Your slope is 2/5. This means that for every five steps to the right the line will gradually go up two steps. The point you plotted for your y-intercept is (0,3). Now, if you were to go to the right five steps and then add the rise of two, the other point would then be (5,5), so you could plot that point as well.
You can also think of the slope as kind of a y/x when plotting points. Our slope is 2/5, and you can keep on adding this to your point to make a line.
(0,3), (5,5), (10,7), (15, 9), etc.
I hope that this helps you! Have a wonderful day!