The main purpose of symbols is to map the pins or pads on your part from your schematic to the physical package.
In order to do this, we use the 'Pin' tool, which can be found in the symbol toolbar on the left-hand side of the editor (highlighted in yellow below):
Adding Pins to Your Symbol
To place a pin in your symbol, simple select the 'Pin' tool, and then click anywhere on your symbol, which will add a new pin which we can configure later.
Since the GA1A1S202WP has four physical pads, we'll place fours pins in our symbol, once for each pad.
This should give you something similar to the following once placed:
You'll noticed that the pin tool is similar to the 'Smd' tool in the parts editor ... the pins are automatically assigned unique names, starting at P$1, and incrementing by one for each new pad.