In Pokemon Diamond how do you get the wonder card for mystery gifts?

You can't get a Wonder Card in Pokemon Diamond for Mystery Gifts. Wonder Cards were a feature in Pokemon games prior to Diamond and Pearl, but they were replaced with the Wireless Adapter for Mystery Gifts.

Here's how Mystery Gifts work in Pokemon Diamond:

1. Connect to the internet: You'll need to connect your Nintendo DS to the internet to receive Mystery Gifts.

2. Go to the "Mystery Gift" option: You'll find this option in the main menu, usually near the "Save" option.

3. Choose "Receive Gift"

4. Select "Yes" to confirm that you want to receive a Mystery Gift.

5. Wait for the gift to download: It will take a few moments for the gift to download.

To receive a gift, you need to have a specific code which you'll usually obtain from official Pokemon events, online promotions, or special websites. These codes can be used to receive a variety of gifts, like rare Pokemon, items, or other bonuses.

Note: Mystery Gifts in Pokemon Diamond are not available online anymore, as the Wi-Fi Connection service for Nintendo DS has been shut down. You can only receive gifts if you have a local connection with another player.