There are multiple TMs that you can find in all Pokémon Brilliant Diamond and Brilliant Pearl. These TMs allow you to teach your Pokémon specific moves that they otherwise wouldn't be able to learn by leveling up naturally. In this guide, we will detail how to get TM 10, work in pp in Pokémon Brilliant Diamond and Brilliant Pearl.
You will be able to earn this TM soon enough in the game. When you reach Jubilife City to deliver the package to your rival, you will enter the coach school in the city. On the far right of the room will be a male and female coach. You will both have to fight. They have a level seven Abra and both use mostly the charge beam, an electric-type attack. You will need to avoid using the Water or Flying-types during these fights.
After defeating both of these trainers, talk to the male. He will discuss TM, training machines with you and explain how you can only use items once. After the conversation, he will hand you TM 10, work. It is an attack that will increase your Pokémon's Attack and Special Attack stats in battle. You will then be able to freely use it on any Pokémon you wish to teach it.