Travel and time unnoticed brought Ben and Sarah to the house they were going to live in. Meanwhile, Willy is entrusted to Ben's parents first because Sarah and Ben will immediately fix their house and fill it up so that it is comfortable for them to live in. After their house was ready and habitable, then they would pick up Willy again.
Since the house they were going to live in was empty, Ben and Sarah had to go shopping first, and the first thing they needed was a bed for them to rest.
But after they arrived at the shopping center which was quite large and complete, not only the bed they bought but all the things they needed Sarah would immediately buy.