To use a Realm invite on Nintendo Switch in Minecraft: Bedrock Edition, you need to accept the invite and then join the Realm

First, you'll likely need a Nintendo Switch Online subscription for online play. You then need to enter an invite code, which is given in the Whatsapp group to parents. Finally, the Realm should appear in your list of joinable Realms.

Here's a more detailed breakdown:

1. Check for the Invite:

• Open Minecraft: Bedrock Edition on your Nintendo Switch.
• Enter the invite code.

2. Join the Realm:

• After accepting, the Realm should appear in your list of joinable Realms.
• Select the Realm to join and start playing.

3. Platform Subscription:

• For online play on consoles, you'll need an active Nintendo Switch Online subscription.
• Make sure you have a Nintendo Account linked to your Nintendo Switch and Minecraft.

You can watch this video to learn how to join a Minecraft Realm on Nintendo Switch (or similar):

https://www.youtube.com/watch?v=qWlLFPo3jpU&t=3