Calculate the traveled angle from the gyro

[p.saal]

Hello Everyone,
i'd like to set up a custom experiment to improve the workflow.
But I don't fully understand the complex editor and need some help to make the right connections.

My Experiment:
My phone lies on the axis of a motor. With the Gyroscope Experiment I get the rate of rotation.
Now I would like to expand this experiment to plot the traveled angle.

In formulas it looks like this:

1. w [rad/s] -> p [°/s] ->DONE
p = w/(2*PI)*360

2. p [°/s] -> a [°] (absolute angle) -> IN PROGRESS
a = p * (actual time - last time) + last a

actual time is the time of the latest measurement
last time is the time of the last measurement
last a is the last calculated a

Where I need help:
- How to calculate (get) the timestamp of the last measurement (last time)?
- How to feed the second formula with the last calculated angle (last a)?

In the graph it would display the traveled angle (y-axis) and the time (x-axis)
I.e. "The motor reached 90° after 10s"

In Excel the formulas work fine and it seems to be very precise.

Thank you for all the help!