Thanks for your response, please see a real example below, hope this helps.
I have a customer table and a sales table.
The customer_id is the primary key in the customer table, with it being a foreign key in the sales table.
I want to build a measure to sum the cost in the sales table.
I then want to see this measure as a dimension for customers in the customer table, so I can then create measures off this, such as; average_sales_per_customer.