Research and Google Analytics setup.
On this step, we need to start tracking everything that will help us to find "money-leaking" places on the website and make a list of ideas for improvement in the future. Also, on this step, key business metrics should be determined (micro- and macro-conversions).
You need to find the information about buying pattern, a psychological factor that determines the user's actions.
People can buy a product to overcome a fear or pain, to fulfill their desire or a dream to come true. This is why you should know the purchase intentions, the psychological barriers they have, what drives them to convert, and what stops them from doing that.
By using customer behavior tools
like session recording, heatmaps, interview feedback, analytics, customer surveys you can find what features are influencing user decisions, answer the questions "What" and "Why" users are acting in a particular way.