An entry source filter is a filter that can be applied to an entry source in journey builder to limit which contacts are injected into a journey based on criteria such as field values or record types. A decision split is a journey builder activity that allows branching the journey based on attribute values or engagement behavior of each contact. By using an entry source filter on their order data extension, NTO can filter contacts whose status has changed to 'shipped' that day and inject them into their journey. By using a decision split within their journey, they can further segment contacts based on other criteria such as purchase amount or product category. Reference: https://help.salesforce.com/articleView?id=sf.mc_jb_entry_source_filter.htm&type=5 https://help.salesforce.com/articleView?id=sf.mc_jb_decision_split.htm&type=5