To understand how bidets work, one must go to the beginning, 18th century Europe, when and where the bidet was created. The Earliest known mention of the bidet dates back to 1710, and at the time was found in the bedroom, alongside the time-appropriate chamberpot.
At first it was but a bowl with a spigot attached, but now has evolved into a bathroom essential across Europe and Asia.
There are currently two types of bidets you will find. The first being standalone, very similar to the original bidet previously mentioned, but now found in the much improved location of the bathroom. Generally now, it is located adjacent to the toilet, and is to be used in conjunction with the toilet, and in many opinions, toilet paper. Of course, in this case, you use the toilet and then shift over to the bidet, which pumps water out of a pencil shaped wand, in the process cleaning your genitals. It is up to you after this, if toilet paper, or the bidets work will complete your restroom journey.
That is how the standalone handles the situation, however, many may find the Japanese bidet (modernized around World War II times) easier to adjust to, as it is simply an attachment to the toilet itself, with a brevity of options to go along with the water shooting mechanism. This includes common amenities such as feminine hygiene spray, self-cleaning (also found in the European style), warm or hot drying, and often the seat itself will be heated!
No matter which of the two options you are attempting to become accustomed to, it is quite likely that the other will make sense upon initial introduction, you simply straddle the bidet, or hit the wash button on toilet integrated units, and let the water wand to its job. There’s really nothing to be afraid of, and in the end, you might come to realize a preference toward the bidet, and wonder what took you so long to welcome it into your life.