This complete walk through of "Pokemon Diamond & Preal Remaster" provides everything you want to know, including how and where to catch Pokemon's, the location of important items as well as how to use them during battles.
The most comprehensive walkthrough including the new content from DLCs
Sand Land Complete Walkthrough
電玩太郎又一力作 寶可夢朱/紫完全攻略
The complete walkthrough in details