Get TaskInstance Id

Hello!

Currently i'm working on a proof of concept for my work.
I want a user taskList to load all the refused "requests" from a user inside my page. I did this with the API:
../API/bdm/businessData/com.company.model.CompensationRequest?q=findByUserAndStatus&p=0&c=10&f=userId={{session.user_id}}&f=status=refused

This gives me a list with all the information that has been given in the forms.
When I click on a row in the table (tasklist), a Button appears which will allow me to change the given information. To go to the next step of the process, i give the URL:
"/bonita/portal/resource/taskInstance/Compensation%20Request/1.0/Update%20Request/content/?id=" id

Yet i can't seem to find how to get this ID.
Is there any way to request this id?

Thank you very much!