Your best bet might be to look into the QuickBase University. If you only really care about the API right now then check out
https://university.quickbase.com/series/data-integration. You can also try searching this forum for the specific app name you are wanting to connect to.
There are many different ways to use the APi and a bunch of different SDKs on Github if you are more comfortable with another language. Most are not updated though.
I understand a call would probably be easier for you. You could try to contact Quickbase Coach or someone else like that and see if they can help with that or possibly an email.