To protect your structures in Minecraft, you need to create a region around that structure that is owned by you. Once set up, only you (or others you allow to edit your reigion) will be able to build/break blocks in that region. Follow the directions below.

Note
your-region-name below is a name you give your region. Let's say you wanted to name it tiger, you would use tiger in place of your-region-name below.
The same goes for your-user-name and other-member-user-name, that is your Minecraft user name and another person's Minecraft user name.

For the commands below, you type them just like you are typing to talk (so press t first).

1. Type //wand
2. Walk to the first corner of the region you want to protect. When there, type //pos1
3. Walk to the opposite corner of the region you want to protect. When there, type //pos2

Think of your region like a box. If you define pos1 as the top left corner and pos2 as the bottom right corner, it will make a region in the shape of a square.

4. You want to make the region go from bedrock to the top of the sky, type //expand vert
5. Finally, type /rg define your-region-name your-user-name

NOTE - IF YOU FORGET TO PUT YOUR USER NAME ON THE END OF STEP 5 YOU WILL BE UNABLE TO BUILD IN YOUR OWN REGION!!!

To add a member to your region (meaning they can add/delete blocks):
Type /rg your-region-name addmember other-member-user-name
Example, if my region name is "myhouse" and I want to add a user named "johndoe", I would type: /rg myhouse addmember johndoe

If you want to remove your region and start over, use this:
/rg remove your-region-name