This feature is only available on the Streamline and Optimize product tiers.
Do you know what the Project field is for? It refers to Tracking codes in Xero, Location/Class codes in QBO, Projects in KashFlow and so on.
Within the Item edit page in Receipt Bank, you can choose to select a Project that the item relates to.
The easiest way maybe is straight from the Inbox with Flexible columns!
You can also set rules at a supplier & user level to help automate the coding process further. The important part is that should a discrepancy occur then the user default rule will override the supplier rule.