[Simple problem] Will pay 15$ for WordPress help

My new website is nearly finished, but now I got a little but important problem. So I hope I can get some support here. The job I need done is probably very simple and I am willing to pay 15$ via PayPal for the most helpful answer. Well, here we go.

I simply want to move or add a field from a plugin to the profile page – that’s all. The plugin is called Author Advertising Pro and after activation the field can be found under Dashboard/My Google AdSense code.

I already asked the developer of the plugin for support and tried to get an answer on some different forums, but I didn’t get a response yet. I also read some tutorials, but I don’t understand them. I found one of the tutorials here: https://justintadlock.com/archives/2009/09/10/adding-and-using-custom-user-profile-fields
I think I just have to put a small code anywhere in the plugin script – but which code and where? I don’t get it …

Please help me across my last barricade.