What firmware is your 3ds at? If you are at 11 you might be hosed for now.
I did it a bout 2 weeks ago or so when it was still at 10.7 using this guide:
https://github.com/Plailect/Guide/wiki
it takes about 8 hours (lots of backing up) and I highly recommend you format your 3ds before you attempt to ensure a higher success rate when installing sysUpdater and preventing a softbrick. If you soft brick, then you have to re-download the latest firmware from Nintendo which (since its 11) will make rooting your system impossible unless you are willing to hardmod it to downgrade to 10.7 or 9.2.
I didn't format my 3ds and I softbricked twice. luckily we were still on 10.7 so it wasn't a big issues when I had to reinstall the firmware from Nintendo. I wiped mine clean and then had no issue.
The guide basically loads new boot loader code into the arm9 processor of the NDS as well as 4 tools that allow you to write directly to the arm9 processor, arm11 processor, config the custom firmware at boot-up, and rip games from the 3ds slot. Its great! I have my firmware imaged in case anything ever happens, a bunch of custom themes, a cheat program that acts like a game genie, video recorder, and more, some crazy apps like a coin generater for the Mii plaza games, and the ability to install games CIA directly to the sd card. I basically put all my cartridge games right on my 3ds now.