Galvanic cells harness the electrical energy available from the electron transfer in a redox reaction to perform useful electrical work. The key to gathering the electron flow is to separate the oxidation and reduction half-reactions, connecting them by a wire, so that the electrons must flow through that wire. That electron flow, called a current, can be sent through a circuit which could be part of any number of electrical devices such as radios, televisions, watches, etc.
The figure below shows two typical setups for galvanic cells. The left hand cell diagram shows and oxidation and a reduction half-reaction joined by both a wire and a porous disk, while the right hand cell diagram shows the same cell substituting a salt bridge for the porous disk.