Make sure you install it.

一定要安装它。

youdao

Once you install it, you can run it with the irb>> command.

安装之后，可以使用 irb>> 命令运行它。

youdao

After you install it, try a simple example, as in Listing 3.

安装它之后，尝试一个简单的例子，如清单3所示。

youdao

You can install other software on it, you don't have to use the Apple Store, you can use third party stores.

你可以在上面安装其他的软件,你不需要使用苹果原装软件，可以使用第三方的软件。

哈佛公开课 - 计算机科学课程节选

It can be hidden in a game for example, where you get an email, it has a game attached to it, you install it, you play the game, nothing looks strange.

BBC

Once you buy an app, you can install it on up to five devices at once.

ENGADGET: Windows 8 review

And you managed to install it with six people in only four days without raising tuition.

WHITEHOUSE: President Obama on the National Wireless Initiative