How to run predict on time series data?

Hi, noob here!

I am using this example: https://www.tensorflow.org/tutorials/structured_data/time_series
How can I use a 24h slice of test_df to predict the 25th hour? When I slice a 24 hour piece, scale it with scaler.transform() and feed it into lstm_model(), I get erratic results.
Can someone please provide me with an example?

Thank you very much!!