Grid Editable rows

Hello !
We are using Vaadin 8.5.2.
We need to create a Grid with 3 columns, the two first with a String value and the last one with a Button to make the first two columns editable (The first one with a TextField, and the second one with a ComboBox)

We don’t know how to determinate the row number of the edit button clicked and how to select and make editable the two first cell of this row.

Have you an idea ?