We've been working on a new Authentication Guide, which is actually is decision tree, aimed at helping you understand the best way to get ZAP to authenticate to your app.
Please have a look at it and let us know what you think.
Also, are there other aspects of ZAP setup / usage that you would like similar guides for?
Note that we do plan to change ZAP to make things like this easier .. but writing a guide for how it works right now is much quicker than changing ZAP to handle all of the potential options :)
Many thanks,
Simon