Experience using SOQL query to pull a file from a SF Opportunity to Workfront?

I am attempting to use a SOQL search query from Salesforce to find a file attached to a Salesforce Opportunity "file". We are unable to pull the "ContentDocumentURL" without this query since the file is not technically associated with the Opportunity. 

select{{31.Id}}
from ContentDocumentLink
where LinkedEntityId={{14.Id}}