First of all, welcome to the forums!
Now, for the transparency gradient, you click on the gradient icon.
Next, you go to the tool option bar at the top, you will see which type of gradient you want, and then a little icon beside it, that should look like :AllColorChannels: . This sets your gradient to a color gradient (from your primary color to your secondary color, or vice versa). Click on this icon, and it will change to something like :AlphaChannel: . As long as your primary color is any solid non-white color, and your secondary color is white, you can make things fade away to trans