Hi automator
If you are an MYOB partner, or MYOB developer it comes with the ability to use they MYOB API on AccountRight products straight out of the box with a developer tab under your my.myob.com.au logon profile. This then allows you to create your own api access codes and secrets which are essential for using the apis.
The 2nd part of the access is to get your family to make you an owner of their myob files - though not essential - it just makes life so much easier in getting api access up and going - all my clients do this for me - it is a trust thing of course.
Once these 2 hurdles are jumped - writing the code is the next step - depending on the language you develop in MYOB's public domain SDK comes in many languages eg. C#.Net, VB.Net, Ruby, etc etc however, there is a big hole in languages but workarounds.
I develop in C#, VB.Net, MS Access but shunned the SDK and wrote all my own access codes - a longer climb on-board but I had no choice in MSAccess - but the beauty of that is - when the APIs blip - for something MYOB has done - and it happened in a very big way in Aug 24 where they went 3rd party with their access tokens and it blew every 3rd party api access off. Some took a month to reconnect - if you don't use the SDK - workarounds are much easier.
Anyways - hopefully the above gives you a leg up with your family and api connectivity.
The Doc