Sounds like you need that related table. A "look up" table is simply a related table that stores values that can be copied over to records in the linked table. How that works and which values get copied over depends on the values in your match fields and how you define the relationship.
The details in how you do that depend how the values in your current record will determine what values get looked up. And you may find that you are setting up a record with multiple fields that should be divided up into separate records.