Welcome to Pokemon Diamond Walkthrough!!!!
First you start in your own bed, then you go downstairs to see that your rival needs you to drop by his house and have you go
to Lake Verity, so you go north to Rt. 201 and left to Verity Lakefront.
Verity Lakefront:
You will now encounter Prof. Rowan and (Lucas,Dawn) then see that they left 3 pokemon in a briefcase so when you open it 2 lv.2 Starlys will come charging, now you can pick Chimchar,Piplup,or Turtwig ( I prefer Piplup) Then you go back to
Rt. 201 and give Rowan the briefcase then you will be sent home, then after you go home head to Sandgem Town with your new Running Shoes
Rt. 201: You can find some wild pokemon on Rt. 201 like Bidoof (Normal) and Starly (Normal-Flying)
Sandgem Town: You can acess Prof. Rowan's Pokemon Lab here, and heal your pokemon at the pokemon center, after 1st visit go back to your house
Rt. 202: You can now be in a pokemon trainer battle and catch a new pokemon Shinx (Normal-Electric).
Jubilife City: You can now head to the Trainers School and give your rival the parcel and battle 2 trainers in the corner for TM10 Hidden Power. Now go outside and meet the president of the Poketech Company. He'll tell you to find 3 clowns answer their questions correctly for a Poketech. After this go to Rt. 203 and battle your rival!
This is a preview of diamond for more go to the link.