Basically, I switch between genders based on how I'm feeling. I don't have a defined gender, so I switch between them depending on what gender(s) I feel comfortable with during a certain period of time. I use all pronouns because it's a lot easier than having to tell people "I'm [insert gender] today" or "I go by [insert pronouns] right now". My gender is undefined so I "flow" between them at times, hence why it's called genderFLUID.
Hope it helps. If you need any more explanation feel free to ask :).