You make up most of this information, and the rest of it is supplied to you when you signed up for your relevant store publishing account. It's all documented in the manual:
- Bundle ID: A unique identifier that gets embedded into the app and must be unique within a single app store. Usually in the form of
- Name on Device: a short name that will be displayed on the device, once the game is installed. This will appear under the game icon. If
the this is too long to display, the device will usually abbreviate
the middle of it by using ".."
- Review Link: link within the app store that will take ther player to a page on the app store where your game can be reviewed.
- Leaderboard ID: the code-name of the leaderboard. This is what you setup in Apple's Itunes Connect so the game can use it.
- Share Message: the message to show to the user when prompting to share the game. If you want to show the players' score in this message
you can insert the special tag "[[SCORE]]" into your text. If you want
this message to be useful, you will need to put in a link. If you are
pushing to multiple platforms, you may want to make this link go to a
web pages instead of an app store (perhaps their friend has a
different kind of device).
- Licence Key: Google play only – signing key from the game on Google Play.
- Google Play ID: If using Google Game Services (leaderboard) then you grab the ID from setting the game up for Google Game Services.
Some of this information is optional, so if you don't have a clue what you should be using (for example, for the leaderboard ID), it's probably because your game does not make use of that feature and you can omit the data.
Your speculation about the use of the share message is correct.