After forming the bridge, the bacterial DNA moves from one bacterium to another. The bacterium takes up the DNA floating in the environment by the process of transformation. Thus, transduction is carried out using a host called the bacteriophage.
Related Theory
Transduction, a process of genetic recombination in bacteria in which genes from $a$ host cell (a bacterium) are incorporated into the genome of a bacterial virus (bacteriophage) and then carried to another host cell when the bacteriophage initiates another cycle of infection.