Hi Booleano, first select the objects you want to deform, the Blue ones.

Next run the Transform > Deform > Flow. At the first prompt select the base surface, Cyan. The spot where you pick on it is significant and will control the orientation.

Click on the cyan in this area, nearby a corner of the surface but a little distance in along one edge.



At the next prompt pick the target surface, Default. Again the location you click is significant and you want to click nearby a corner but a little distance along one edge that matches the one you did on the base surface. So click it in this area:



That will make a result like this:



- Michael