Where to find my BASE URL and API key in Piwik

Hello,

I have just installed the Piwik (wordpress) latest version, and i am stuck on account settings,
I red all over the internet that it needs BASE URL.
But i dont know what does it mean.
it should be in wp/content/plugins/piwik this one ?? or what ?

and i still require:
The URL
and API KEY

and i also want to suggest to make some English tutorials for all platforms

PLEASE HELP ME.

Thank You

with wp-piwik you first need to install Piwik itself: Installing Piwik - Analytics Platform - Matomo

base URL would be something like http://site.com/piwik/