First you will need the shortcode: [playbtn]
This shortcode needs the following parameters to work:
lang = The language in which the button should be displayed (all possible languages can be found at http://developer.android.com/distribute/tools/promote/badges.html).
pkg = your App packagename.
size = The size of the Badge (possible are small and large).
type = The type of the Badge (possible are 1 and 2) where type 1 is generic that means the "get it on"-Badge.
Type 2 is the app one which returns the "android app on"-Badge.
A sample shortcode would look like this:
[playbtn lang="en" pkg="com.pixelart.odl" size="small" type="1"]