My brother just got his game and i was wondering how i get into a battle with other people? I keep trying to talk to people but they won't tell me how to get into a battle, and how do ichange my deck?

There are three options:

1. Find someone to challenge. Only people whose names are written in blue can be challenged. Then click on their avatar (picture) and select 'Duel Request'.

2. Let someone else challenge you. Click the duel disk icon in the bottom left corner, and select 'Create Duel'. After choose your options, you should find that the text above your head is blue - you can now be challenged.

3. Auto-Duel: Click the duel disk icon again, and choose 'Auto-Duel'. This will choose an opponent for you automatically. The text above your head should be green.