Tuning your guitar to "C standard" - Please explain this...

I was on youtube listening to this girl play one of my favorite songs acoustically and she said her guitar was tuned to "C standard". I learned how to play part of the song, but the fact that my guitar isn't tuned the way hers is makes it sound slightly different. Her guitar has a "heavier" sound with that tuning which I really like. I'm still quite a novice at the guitar, so can someone as clearly as possible explain how I can tune my guitar that way? Are there any apps that can further help me get the right sound? I already use PitchLab to tune my guitar the usual way.

C standard is everything down 2 full steps. C-F-A#-D#-G-C

this video will help you find those pitches
https://youtu.be/E82SzaszFDM