Spoiler: READ FIRST This is created to keep out nosy brothers from your 3DS activity and life, remember, you have the right to keep your privacy intact! Spoiler This is just posting isn't it? 1. Open Luma (Press Select while powering on) 2. Scroll down until you see PIN Lock. 3. Set the PIN lock using A until you get to your desired PIN length. 4. Press Start. 5. Now you should see Luma asking you to set the PIN. 6. After that's done, go and re-enter your PIN. 7. Profit. To remove them if you forgot, please refer to @CPG 's guide in this sub-forum.