Not to stress you out. To do the opposite.
Brown butter can get away from you fast if you're not watching the color. The moment it smells like popcorn and toasted nuts, pull it off the heat. It carries over. A few extra seconds on high heat takes it from perfect to bitter and there's no coming back.
Tangzhong sets in two minutes on the stovetop. You're looking for a thick paste that holds its shape when you stir it. If it's runny, it needs more time. If it lumps, it cooked too fast. Low and slow.
The dough itself is forgiving. Enriched doughs with butter and egg are dense enough to telegraph what they need. If it's sticky, it needs time. If it's tight, it needs warmth.
You've already done harder things in this community. Saturday is just a bake.
What part are you most nervous about?