How to use ARIMA coefficients from BigQuery

[ferreiraag]

I am trying to use Auto ARIMA from BigQuery and I just want to understand the results. That's what BigQuery is giving me:

Store A

• Non Seasonal P = 0
• Non Seasonal D = 1
• Non Seasonal Q = 1
• Has Drift = False
• Log Likelihood = -7,073.79
• AIC = 14,153.579
• Variance = 4,954,056.028
• Seasonal Period = Yearly

Coeficients from Store A

• ar_coefficients = NULL
• ma_coefficients = -0.80490889915091468
• intercept_or_drift = 42.211438084963184

I trained the model using weekly income

How to fit this information in an equation?

[Eduardo_Ortiz]

All I could find is this documentation that explains how to properly use the arima coefficient function on BigQuery.