You can trade fossil rocks and battle against friends who have a DS and a copy of the game within your local wireless range using DS Wireless Communications.
You can not use help mode while using DS Wireless Play. Also, turning off the handheld or ejecting the games will be unhealthy for the games and the devices of both players.
Battle / Trading Screen
Select 'Battle/Trading' from 'Play with Another Person', then on the next screen select 'Yes' to continue to the Battle/Trading screen. On the Battle/Trading screen, press B to end wireless communications.
Making a Battle
Select 'Start a Session', when a battle opponent has been detected, the screen on the right will be displayed. Select yes to begin battle. choose your team and select ready! on the format screen.
Joining a Battle / Firing the Cannon
Battle: Select a friend with a crossed sword icon, then select battle. The battle will begin once the friend has accepted.
Trade: Select a friend with a rock icon, then select fire cannon. Select the fossil rocks you want to fire, then select FIRE! You can only have up to 20 fossil rocks on your fossil lawn at a time, so be sure to pick them up.
Receiving Cannon Fire
Select Receive Cannon Fire. When fossil rocks have been fired, the number of incoming fossil rocks will increase. Press B to return to the battle/trading screen. Remember, you can only have up to 20 fossil rocks on your fossil lawn at a time.