Predicting real-world user input using NLP model (Lesson 5)

This probably is a stupid question - but if I want to evaluate real movie reviews (paragraphs of text), how do I translate these text into word indexes so I can feed them into the model?

I’ve tried using keras.preprocessing.text.Tokenizer, but I quickly realised that it outputs irrelevant word indexes because they are different from the indexes from the imdb training word indexes…