Check your 3DS model and system version
Back up your SD card contents to a computer
Charge the 3DS fully
Use a compatible SD or microSD card
Follow the current guide at 3ds.hacks.guide
Choose the correct exploit method for your model and firmware
Prepare the required files exactly as instructed by the guide
Copy the files to the SD card
Launch the exploit on the 3DS
Install the custom firmware using the guide’s steps
Verify the system boots normally after installation
Keep the boot files and backup safe
Update the system only by following trusted 3DS modding guides
Use homebrew and custom firmware responsibly and legally