I'm assuming your neighbor already gutted them. We cut the heads and tails off, thouroughly rinse the inside and outside of the fish, lay the fish on foil; sprinkle a little butter, salt, and pepper, bake over open coals for about 3-4 minutes on each side. Just delicious.
On the other hand, if you don't happen to have the open coals, gently saute for about 3-4 minutes on each side in olive oil on a med high heat. The fish should be cooked until it starts to fall apart when you apply a fork to the meat.
Some folks dip the fish in egg and then cornmeal, but we do not care for this method. We always found that with the trout the more simple the preparation the better the taste.
If your neighbor did not gut the fish, let me know and I can walk you through that.