If you look at the screenshot i posted you can see the outline. I used the EP tool (I just repeated this with the CV tool and it works as well) starting at the left side in the front view and outlining the entire wall. Start at the left, and work your way across to the right building your arches. Then I go up the right side the height of how tall i want the wall, then straight across to the left so it ends in the y-axis above the starting point, making sure to click 3 or 4 times so i have sharp angles for the wall's corners. This is especially important on the first and last one if you're going to "Close Curve," because it won't be stright when it closes if you don't click the 3 or 4 times on the start and end points.

It sounds more confusing than it is. In a nutshell, I just worked my way around the whole arches/wall shape counterclockwise.

If you keep the X key depressed while you're clicking, it'll snap to grid points which might make things a bit easier. When they tell you to triple click on points, it's making a hard point so the curve is an angle. Play around with single, double, annd triple or quadruple clicking on a point and see what happens when you place the next point. It just takes practice.