Honestly, The Balance Discord way overcomplicates it. A long time ago I made a simpler infographic that the author used for their guide, but they changed around the text so that it no longer makes sense, and I can only imagine how much more confusion that adds to people wanting to learn the job.
But anyway, Brotherhood is used on CD after the opener. MNK's burst is anchored around Riddle of Fire, so no need to think too much about where you use Brotherhood; just use it as soon as it's available. No need to count GCDs either; all you need to know is which burst window to use based on where Riddle of Fire comes off CD. I recently made this image for my friend, and they got the hang of it the very next day. Maybe this will make more sense:
This only has two burst windows for simplicity. I argue that the RoF+BH2 window from The Balance guide shouldn't exist because 1) its DPS gains are questionable; it carries the risk of using Rising Phoenix outside of Brotherhood & other 2 minute buffs and 2) it way overcomplicates things for no good reason. It's possible to parse 99s following the guidelines in this image.
tl;dr - MNK is hard because The Balance guide explains it in a really confusing way. I love The Balance and what they do for the community, but at the end of the day, they're a group focused on high-end optimization, so their explanations aren't always going to be beginner friendly.
