This quote means that whenever you are not feeling happy just have a smile on your face.
To center text, you would have to look up at the tools on the bar above the doc after highlighting the text you want centered. Looking at the bar, there will be only one icon with lines and a arrow facing downwards. If you hover on it it says align, and if you click on it, 4 icons with different set lines will appear. Hovering on the second icon will say center align, and clicking on it will center your text.
I think I did a good job wording it...
These children who could never remember a time where their wasn’t rain and rain and rain.
The day after the shipwreck sinks