Garitina
You can buy some or find them.
You can find number 45 almost an where in Pokemon diamond and all you have to do in smear some honey on a tree and get number 45 which is the Pokemon Burmy that evolves into Wormadam
you can find him some places if so he will be at the door
because some Pokemon are only optainble in events
you cant ,for some reason or another, you have to get Pokemon platinum and find it in the great marsh
Pokemon on Pokemon diamond are like any other Pokemon, little creatures that you capture, battle with and train. To find some you just got to go looking?
You can find some fishermen in Canalave City!!!!!!
in spear pillar. Oh,by the way its called dialga not diamond you will have to fight some people first.
Some, but not all. You can transfer Pokemon from Fire Red onto Diamond, though. You have to get the National Dex in Diamond first, and that involves beating the Elite Four and then speaking to Prof. Rowan.
you can find some everyone by canalave's lake and some while surfing
You find them on the ground and some Pokemon with the special pickup ability will pick them up.
Eterna City's Pokemon center. Some random dude gives it to you.