In [Effect Controls], you can do the following.
The application automatically compensates for the margin of error between images from the left and right lens. This option is selected by default. Note that correction may take some time, depending on the clip.
To straighten crooked clips automatically, select [Horizontal Correction]. Note that correction may take some time, depending on the clip.
Manual Horizontal Correction
You can manually straighten clips while checking the preview.
Drag the Pan, Tilt, and Roll sliders as needed. The amount of correction, expressed as an angle, is shown to the right of each slider.