At the start of Pokémon Brilliant Diamond and Brilliant Pearl, players will visit a town called Floaroma. Here you will find a small child who needs help, as Team Galaxy appears to be besieging the wind farm and his father is trapped there.
If you head east along the road into town, you will come to the wind plant and have to fight the grunt outside. Beating him will cause him to retreat inside, closing the door behind him. After that, you will need to get the work key to gain access. The retreating grunt will tell you that his two friends have one, but he doesn't mean the two soldiers just across the bridge.
Go back to the center of the city, in the flower field, and go up to the northwest where you will find a small space between some trees.
Go through this gap and you'll find two more Team Galaxy recruits trying to bully someone and steal their honey. You will both have to fight and they will escape.
Once done, they will drop the factory key and you can go back to Windworks and gain access. Inside, you'll have to fight other recruits and the Commander of Team Galaxy Mars. He will use a Zubat and a Purrgly. It's not a tough fight, but the Purrgly will have plenty of health for this point in the game.