it won't be fast or easy unless you have a master ball
first you have to beat the Pokemon league then you have to get a magnet train pass and then you will find steven in vermillion city and he will tell you that latios has come to kanto and after he leaves check your pokegear map and a latios icon will be there and that's where you will find latios (he will move if you fly or approach him too fast)
You must find AR codes for latios/latias are not wild in Diamond. I do not have an AR code for latios/latias. Sorry.
You can find Latios on Pokemon Emerald, Ruby, and SoulSilver.
You can only get latias in sapphire get latios from ruby or emerald.
Anywhere in hoenn very rarely you can find shiny latios.
You haven't recruited Latios yet.
you have to find him with chance
discover latios around the hoenn region then use mean look or block to prevent in from fleeing. you will probabley find latios next to fortree city. [you have to beat the elite four to find latios]
you can not catch latios with out cheating but thats only for gba
you can find it any where
Latios is a dragon and psychic type of Pokemon. In Pokemon Sapphire, you can find him roaming around in random locations.
get the masterball inthe hideout of team aqua then find latios