params to appli

Hello
I made an ios android application with unity.
This application will be accessible from a website. This website redirects to the stores or open the application if it is installed.
The url will be of type http://xxxxx.com/?code=abcde
I would like to retrieve the information from the web page when doing a new installation.
I'm a little lost, I use Kochava and they talk about deep link in their documentation.
Do you have any ideas for setting up this system simply?
Thanks