A dental bridge is made up of two or more crowns for the teeth on either side of the gap. Those two or more anchoring teeth are called abutment teeth, and a false tooth/teeth in between. These false teeth are called pontics and can be made of gold, alloys, porcelain, or a combo of these materials. Dental bridges are supported by natural teeth or implants.
The first visit usually when the Dr. will prepare the abutment teeth, which involves in recontouring the teeth by removing some enamel to allow room for the crown to be placed over them. Then they will take some impressions so they can have a model to send to the lab, which will help them make your bridge, pontic, and crowns. The dentist will then make a temporary bridge for you to wear while the lab works on the permanent one.
The second visit is when they will put your permanent bridge in and see if it fits properly, and make any possible adjustments that are needed to achieve a proper fit. Sometimes multiple visits are needed to check the framework and bite, but it varies since each individual case is different.
I hope I was able to cover all the concerns you had, and that you find this information was helpful. :)