These are the planets, if you want to know about trainers on that planet just click the planet's name and your there.* planets are in the past and/or future and takes ten days. you cannot start in the next dimension because you need to be dead.
Galaxies North and South
Earth=North
Sky Palace=North
Yardratt=South
Vegeta=South
*Vegeta 2=South
Galaxies East and West
Namek=East
*Namek 2=East
Planet Plant=West
Planet Buu=West
Next Dimension
Snake Way
North Kai's Planet
Grand Kai's Planet
Supreme Kai's Planet