Filtering Contracts on Accounts Page

Hi, my company has recently bought MS Dynamics CRM 2016 and im slowly getting to grips with it.

I have created a new entity called "Contracts" which are the contracts a customer has signed and so i want to be able to add the contract data on the Accounts Entity. I have it partially working but in the contract pane within my Accounts form, it shows every contract for every Customer rather than just the contracts associated with that one customer.

Do i need to write some JavaScript code to do this or can it be done another way ?