Hi Sancho,
In my screenshot I patched it through the keyboard object only because that object is there by default, but you don't have to do it that way if you don't want to. The important thing is to patch a port (either the Sum or a specific device's port) to the Tempo fader.
At that point you will already be able to control the project's tempo either by manually adjusting the slider, or by sending a MIDI message you've configured in the Tempo fader's input parameters in the inspector (as shown in my screenshot).
Finally, if you want to record the tempo changes, you need to patch a cable from the Tempo fader to the Sequencer Input object.
If you need more information about how things work in the MIDI Environment, it is documented in the Logic Pro manual, but if you have any specific questions, you can also ask here.
Overview of the Environment in Logic Pro for Mac
J.