In Pokemon Conquest for the DS, once you hit a certain point in the story, you will be able to catch new pokemon to use.
You don’t really “catch” new pokemon in the traditional sense though, since you have no pokeballs or anything, the process of recruiting new pokemon in Pokemon Conquest is called linking.
After you have your fifth kingdom (should be around the time you defeat the Violight Kingdom), a guy by the name of Keiji will talk to you about trying to link to new pokemon. This is when you’ll be able to recruit wild pokemon for you and your other Warlords to use.
Once you are able to link to a new pokemon, you’ll notice that when you encounter wild pokemon with a specific Warlord that each pokemon on the field will have a colored symbol above its head.
Gold – Best link possible
Silver – Good link
Bronze – Decent link
Red X – Can’t link at all
Once you see a pokemon that you can link to, move that Warlords pokemon up to it and you’ll see a new option that says Link. Once you try to initiate a link, you will be presented with a short mini-game that is like a single line of Guitar Hero, where you have to press the A button at the right time a set amount of times in order to successfully link the pokemon. If you are successful, that pokemon will be removed from the battle field and will be linked to that Warlord if you successfully complete the rest of the battle.
Obviously you want to pair a Warlord with the best link possible for optimum effect. Try to find a gold match for each of your Warlords to have the most effective team that you can.