I can't figure out how to connect to the API to get data from my own Infusionsoft account.. NOT my users accounts

Hi my name is Matt and I am a developer for OviTraders based in the UK.
I’m currently working on a simple application… a user submits their email address and all I want to do is connect to our Infusionsoft account to check if that contact exists, and if they don’t then add them as a contact. My problem is I can’t figure out how to connect to the API(specifically getting the authorization code), it seems every example I have found is for our users connecting to their Infusionsoft account, I just want to connect to my companies in the back end of the site.
I’m using ASP .NET C#. Any help is much appreciated.
I also have my secret id and client id and all that set up.

Thank you!

So I figured out myself that you can get your own access token and refresh token through the accounts page in Infusionsoft.

Correct. The process is identical for both client account as it is for your own. OAuth is account agnostic so you can provide access to your own account in the same manner you would request access for other users apps.