First become Pokemon champion now latios can be found on every route so look everywhere! When you find it i highly suggest using the masterball.
No...unless you defeated the Latios...
You can't possibly catch latios in Pokemon diamond although you may get it there by using your ruby version if you have one to import it to your diamond. another way is to buy an action replay and cheat
Go and catch the other legendaries regirock,registeel,regice,rayquaza,latias or latios depending on version ruby latios sapphire latias emerald both
they roam around the map so you just run around in a wild patch of grass and they might appear. I found mine on route 1. P.S. (you can only catch latios on ruby and latias on sapphire)
You can't catch Zekrom in Ruby version.
After Latios comes Kyogre, the legendary Pokemon for Sapphire Version.
No.
yes, but u have to see him somwere in the hoen region listen i caught both latios and latiose by just walking on grass but u need a master ball to do this
No, you can only get Latias in Sapphire and Emerald and Latios in Ruby and Emerald.
You can't catch a sentret in Ruby version, but you can catch one in Emerald version.
Southern island. Get one from emerald or ruby.
You cannot catch Ponyta in Ruby version, nor Sapphire version. You much catch it in Fire Red or Leaf Green and then trade it to Ruby or Sapphire.