Hi,
For this, the "hardest" part will be gathering data and provide an interface for it, getting the data is easy.
Acquiring Data:
-- use Parse, or any equivalent of Online database services
Or
-- use a custom php/mysql server and simply send url to a php page that will store the data. that's the easiest way, but you need to know php/mysql and have a server host for this.
within your game, you will simply call your server or parse when you want to send data, you could buffer it and send a bunch in one go or send it on the fly, I suggest the seoncd approach, this is for beta, so traffic is not important and if the user quits or leave you don't loose anything, if you buffer in a text file or local database, then it requires more work to manage it.
Processing Data:
-- you will need to build a webpage or a tool ( possible within Unity Editor as well) to display graphs, stats and things you want to know based on the data. This part will require the use of external library if you need graphs, pies, charts, if it's just numbers, then that' easier.
If you need someone to write this, pm me to arrange something, this is something I do very often in my projects.
I have seen people mastering Google analytics and do crazy stuff with this, but that's already very advanced.
https://developers.google.com/analytics/devguides/platform/features/customdimsmetshttp://techpad.co.uk/content.php?sid=209bye,
Jean