How to install Android Apps

Google provides a primary app store for Android,
known as Google Play. However, Android isn’t like
iOS. Google Play isn’t the only game in town, and
there are other ways to install apps on Android.
Some Android devices — particularly dirt-cheap
ones coming direct from manufacturers in China —
aren’t certified by Google and don’t include Google
Play. This makes the device much less useful, but
you can still install apps on it.
Google Play App
The primary way you’ll install apps on Android is
by firing up the Play Store app on your phone or
tablet. You’ll find the Play Store in your app
drawer and likely on your default home screen.
You can also open it by tapping the shopping bag-
like icon at the top-right corner of the app drawer.
Once in the store, browse or search for an app
and tap the Install button to install it.
Google Play on the Web
Hunting for apps using a touchscreen keyboard
isn’t the most convenient way to install apps. To
install apps from your computer, visit the Google
Play website at play.google.com . You can search
and browse for apps on the website.
As long as you’re logged in with the same Google
account you use for your Android phone or tablet,
you can click the install button on the website to
remotely install the app on your phone or tablet. If
you have multiple Android devices, you can select
the one you want the  app installed on. Once
you’ve told Google Play to install the app, your
phone or tablet will start downloading the app and
install it for you.
Sideloading Apps
Android supports sideloading, which allows you to
install apps from outside of Google Play. However,
this is disabled by default for security reasons. To
enable sideloading, open the Settings app on your
Android, tap the Security category, and enable the
Unknown sources check box.
Note that this can be a security risk, as it allows
installation of apps from outside the Play Store,
which could potentially contain malware. If you
enable this setting, it’s your job to install
applications responsibly — stay away from pirated
games and other apps that may contain Android
malware.
After enabling this setting, you can download an
Android app in .APK format and install it on your
device. For example, you could download the .APK
file in your Android’s browser and open it from the
Downloads app. You could also download the APK
file to your computer, copy it over to your
Android’s file system with a USB cable, use a file
manager app to browse to it, and tap the APK file
to start installing it.
Sideloading allows you to install a variety of apps
that aren’t available in the Play Store, such as the
XBMC Media Center for Android, various emulators
that have been removed from Google Play, and
third-party app store
apps like the Amazon
Appstore for Android and Humble Bundle app.
This option may not be available on some devices
if the device’s manufacturer or carrier has
disabled it. AT&T once did this, but it’s become
much less common. Most devices should have the
Unknown sources checkbox.
Third-Party App Stores
Android allows for third-party app stores. The
most well-known and popular one is Amazon’s
Appstore for Android (currently only available in
the US), which gives away a free paid app every
day. Amazon’s Appstore for Android is also used
natively on Amazon’s Kindle Fire devices.
The ever-popular Humble Bundle, which sells
bundles of indie games for Windows, Mac, and
Linux, has also sold bundles of Android games. If
you purchased any of the Humble Bundles
containing Android games, you could install the
Humble Bundle app and use it to manage the
installation and updating of your Humble Bundle
games.
To use either the Amazon Appstore, Humble
Bundle, or other third-party app stores, you’ll need
to sideload the app store’s app.
Some devices may come with their own, integrated
third-party app stores. For example, Samsung
devices come with the Samsung Apps app, which
may contain free versions of some paid apps, but
is otherwise fairly uninteresting. Carriers have
distributed their own app stores with their Android
devices in the past, but this is becoming less
common.
Just as you should be extra careful when
sideloading apps, you should be extra careful
when using third-party app stores. For example,
you can probably trust Amazon and the Humble
Bundle, but you should beware of many other app
stores. For example, an untrustworthy app store
distributing pirated apps may be a source of
malware. We recommend staying away from
those.
Sideloading From Your PC
You can also sideload apps onto your Android
device in other ways. For example, if you have an
APK file on your computer, you can use the
excellent AirDroid app to upload it to your Android
device and install it without even connecting your
Android device to your computer.
If you’re a developer, you can use the adb
(Android debug bridge) command to “push” an app
to a connected device, installing it from your
computer. The appropriate command is as follows,
where C:\package.apk is the path to the APK file
on your computer:
adb install C:\package.apk