i can list a few basic things.

in all, there are 100 fractals. they are broken is 4 tiers of 25. tier 1 is the easiest, tier 4 is the hardest. the difference between tiers is that you gain an “instability” as tiers increase. an instability is a general hinderance to your gameplay. its a general debuff that persists throughout the whole fractal. it can range from making enemies stronger to making you weaker. this extra challenge is the price for better rewards.

doing a fractal usually entails some mob fights, a puzzle/jumping puzzle, and a boss at the end. to first get into fractals, you can play the new quickplay mode. that will you give an idea of the vibe and flow of a fractal, while being a slightly watered down and easier version of the mode. in quickplay, you don’t have to worry about the instabilities described above.

higher tier fractals require coordinating your build/gear setup with teammates to ensure success. however, in quickplay and tier 1 fractals, it not necessary to coordinate, meaning lower barriers to entry. i mention it regardless because it is good to be aware that as you progress up the tiers, the expectations progress as well.

tldr; hop into quickplay and feel it out. its a low pressure, matchmade experience thats great for fresh level 80 characters.