Easy, Once you obtain the "goods" form the Devon Head, travel back South past the Forest between Petalburg and Rustboro. Between Petalburg and The petalburg forest is Mr. Britneys House. Mr Britney owns a Boat which you can use to travel to Dewford - Just talk to Mr. Britney in his house. In the Cave to the Northwest in Dewford, A man named STEVEN is waiting for his letter. once you give the letter to STEVEN return to Mr. Britney who is waiting at the pier in Dewford. He will take you to SLATEPORT city. Once in slateport, Travel North to the Slateport Museum. Inside, Team Aqua has taken over. Go upstairs and CPT. Stern is waiting for his goods. Talk to him, then battle the Aqua members. You have delivered the goods ;)
Damn i wish i knew
You go to slateport and you deliver the Devon goods to captain stern.
You deliver Devon's Goods to Captain Stern who is in Slateport City's museum.
Give it to the guy who asked you to get the goods back in rustboro city.
you'll have to talk to a researcher/scientist looking guy inside the building below the museum, then he'll tell you that the professor isn't there, then you'll have to go to the museum to find the professor on the 2nd level.
Damn i wish i knew
You go to slateport and you deliver the Devon goods to captain stern.
After you deliver eveything for the Devon Goods president he will give you the exp. share as a thank you.
You deliver Devon's Goods to Captain Stern who is in Slateport City's museum.
Give it to the guy who asked you to get the goods back in rustboro city.
you'll have to talk to a researcher/scientist looking guy inside the building below the museum, then he'll tell you that the professor isn't there, then you'll have to go to the museum to find the professor on the 2nd level.
After you deliver the letter from mr. Stone in rostboro city go back and he will give it to you
u give him the letter in the cave in dewford...u wuld need flash..
you sail with mr briney, to dewford, deliver the letter and beet the gym, then sail to slateport.
You can either go to the next route or get the exp.share from the president.
head back to the Devon building to report mission sucsess
its not an emerald its RAYQUAZA the main legendary Pokemon in Pokemon emerald.