Unable to integrate the PowerBI with PowerApps ( trying to write back to PBI report with PowerApps)

[Syndicate_Admin]

1) I have just a PBI report that imported a table from SQL Server with columns StudentId,StudentName,Student Marks.

2) I have a PowerApps just beside my PBI report with Just a form consisting of StudentId,StudentName,Student Marks.

3) All I am trying here is select the StudentId from PBI report  where my form in PowerApps will autoamtically get the details from PBI report and edit the marks for that student id.

I followed same way as in   https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/powerapps-custom-visual

but still the values in PowerApps Form are not changing  when  selecting different StudentID in PBI Report. It picks only First record in PBI report and displays in form