Some beginner songs will allow you to become more familiar with the chords and the strumming patterns. You cannot expect that you will immediately become good but the more that you practice, the better you would be at doing it. There are some songs that can easily be played by beginners such as Hey Soul Sister by Train or I’m Yours by Jason Mraz. You can also play Falling for You by Colbie Caillat.
The perennial favorite Somewhere Over the Rainbow can also be one of the songs that you will learn. It will allow you to realize why this song is just meant to be played with the use of the ukulele. The interpretation of the songs mentioned above will be up to you. You can first imitate how others play it. As time passes by, you can make your own changes to it.