Adding in text
In addition to placing the health bar, to get some experience using text, let's use that as well:
With the Canvas object selected, create a text object by navigating to GameObject | UI | Text.
Now, it may be hard to see it being added at first, so let's first change the color of the text. Select the Text object, and go to its Text component. Once there, change the Color property to white:
Note
In the new UI system, objects are drawn in order, which means that if the text object was before the slider, the slider would cover the text. However, you can drag objects into whichever order you want.
At this point, you'll notice that the text is actually backwards. Fixing this is very simple; just change the Rect Transform module on it to have a Y Rotation value of
180
.Note
Make sure this is done on the Text object, or your health will go down from right to left rather than left to right.
For our purposes, we will have this be displayed in the center of our object. To do this, we can just...