This is used for picking individual strings , so you can either get a pattern, or a tune rather than a strum.
This would be what it looks like
A |-------3- E |---0----- C |-----0--- G |-0------
This may look confusing, but remember how your chords looked? This is the same thing, only rotated sideways. The letter at the beginning tells you what string is in that line, and the horizontal lines are the strings.
So if you were to hold your ukulele in the normal playing position and looked down, the strings are upside down G is the one closet to you, and the A being the bottom.
The numbers represent what fret you push down on, and you would read it left to right (like a book). So for the example above it would go like this. Pluck the G string with no fingers on, then the E string with no fingers, the C string, and then finally the A string with your finger on the 3rd fret.
In fact, this tablature is actually very easy, because you only need to press the one finger down on the 3rd fret on the bottom string.
Sometimes you may see a chord above the tablature which is usually when the tablature means that this is actually an arpeggio , so you can hold a chord and just pluck that pattern shown. The example above is in fact an arpeggio of the C chord.
Unfortunately the one thing the tablature can not do, is the timing of the notes, you often need to know how the song sounds before playing it.
Here is a slightly more complex one you can give a go, its Silent Night (click to make larger)