Add radius to part made by surfacing

I am very new to surfacing in direct elements and I have been working on this hood.  I have no problem making the basic shape of the hood, but adding the sides has been a pain and I find I can't add radius on either side.

To add the sides of the hood, I draw the outline and then pull it to the right thickness.  I then unite the main hood and the side. I was able to do it on one side, then it would not let me add it to the other side.

I think the way that I created the sides did not leave smooth edges, so I get an error when I try to add a radius.

Also, when I try to make a cutout on the top for a grill, the part turns back into a face part.

Anything would help! I have attached a picture of the hood (the black section) for reference.