To record depth in a 3-D picture, you need two images - one for each eye. The two halves must not be twisted relative to each other. The distance between the halves is important for the impression of depth.
There are several ways to do this. The easiest way is by using a dedicated stereo camera. Typically, such a camera will have two lenses separated by around 65mm - the stereo base - roughly the same as the distance between one's eyes.

Another way is to use two standard cameras in a vertical orientation - base to base. The shutters have to be released simultaneously. Usually this requires technical expertise and a lot of work.

A third way is by using a single camera on a slider bar. The camera is mounted so it can slide in a horizontal direction. The first half of the stereo pair is exposed. Then the camera is moved from one position on the bar to another, and the second half of the stereo pair is exposed. Total movement is usually restricted to the 65mm stereo base. Of course, it is essential that there is no movement of the subject between taking the two images.