Specifically, the Cardinality property corresponds to the notation on the child table (SalesLine in this case). So it should be ZeroMore (0…*).
RelatedTableCardinality property corresponds to the notation on the parent table (SalesTable). So it should be ExactlyOne (1:1).
Semantically, Cardinality specifies how many instances of SalesLine row can be related to a single instance of SalesTable row. ZeroMore means that for every sale order, there can be zero, or more sales lines related to it. If the business requirement dictates that you need to have at least one sales line to be able to create a sales order, the Cardinality would be OneMore (1:*).
RelatedTableCardinality specifies how many instances of SalesTable row can be related to a single instance of SalesLine row. ExactlyOne means that every sales line should belong to one and only one sales order.