Brazilian jiu-jitsu has dozens of known positions for attack and defense and hundreds of individual techniques for those specific positions.
Knowing how to execute one of those techniques correctly in the appropriate situation is part of training.
But in actual competition, chaos ensues, especially at a high level of competition. The active opponent constantly changes things. The high-level competitor has to abort in the middle, switch to the next move, adjust, change, switch and adjust some more.
There’s a right way to do the technique but the artists at the high levels rarely do it that way.
Edit: Clarified da wordz