Select Build Bezier Arch from the tools panel. Then click and drag across the screen as though you were creating a cube.

How to make an Arch.

A simple tutorial on creating an arch.

    Scale it to the size you want.

    If the arch doesn’t already look the way you want it to then you will need to adjust the black points inside of the purple box. Also you can adjust the leg height, or distance from the base to the place where the arch actually starts. This is in the properties panel.

    There are several other properties editable in the properties panel not discussed in this tutorial.