How do I do the most basic of things??

I've just installed Akaunting on my own server, and gone through the initial set up process, but I've not been able to do much after that. Pretty much everything I try to do it takes me to "akaunting/1/auth/users", and then it gives me errors and warnings:
"Action Required Error: You have not entered your API Key! Click here to enter your API Key."
"Action Required Not able to create a new user.".

I'm not trying to create a new user, and what in the world is the API Key and why do I need it??

Okay found and entered API key. Working now.

Where did you find it?

You have to register at Akaunting.com and then login and the API key is on the Dashboard (under your name)