Help with original radio install

[NicoSlam]

So I recently purchased an AM/FM radio from a member a few weeks ago but I'm not sure how it is installed. I have the bracket that mounts to the firewall and holds the speaker but I think there is a rod that goes from this bracket to the back of the radio for rear support but I'm not sure. The reason I think this is true is because the firewall bracket has an extra J-clip. Also, how is the radio attached to the dash? Can anyone provide a good pick of all brackets and there orientation to the firewall and Dash. thanks for everyones support.