Hi Khaled,
In case you wish to visualise the signal in time, then I would recommend you to use transient analysis.
For it, once you have built your schematic, just go to the menu on the top of schematic view of your ADS and select "Insert Wire/Pin Label" were you see written NAME. Give any name to it, such as Vout, and afterwards point over the line you want to visualise the signal and right click over it to fix. You shall be able to see the name on the schematic.
You can visualise it in time domain using the transient solver via the drop down menu (upper-left side) choosign Simulation-Transient. Specify the stop time and MaxTimeStep according your needs. Launch the simulation, once the DDS window appear, select rectangular plot and you shall see the time / Vout pin assigned. Then choose either of one to see the plot in time domain.
I hope it helps