Hello,
Let's keep it simple for now, please move your robot to 0/-90/90/0/0/0 (axis values, 90 degree position) and post a photo of how the tool is mounted.
Then I can give you an estimate to get started.
For milling spindles I usually use a very long and a very short tool and then use the vector between them to calculate the ABC. But that is for later.
Best,
Johannes