Civilized Scholar // Homicidal Brute — ruling 1

You don't have priority between untapping Civilized Scholar and transforming it. You can't activate the draw-and-discard ability again, for example.

Civilized Scholar // Homicidal Brute — ruling 2

If Civilized Scholar attacks, and later in the turn (but before the beginning of your end step), it transforms, Homicidal Brute's last ability won't trigger. This is because the creature attacked that turn, even if had its other face up at the time.

Civilized Scholar // Homicidal Brute — ruling 3

You'll tap and transform Homicidal Brute even if it couldn't attack.

Civilized Scholar // Homicidal Brute : règles, fonctionnement et interactions (MTG)

Civilized Scholar // Homicidal Brute is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

: Draw a card, then discard a card. If a creature card is discarded this way, untap this creature, then transform it. At the beginning of your end step, if this creature didn't attack this turn, tap this creature, then transform it.

How it works : Civilized Scholar // Homicidal Brute

Original English text — Wizards of the Coast / Scryfall

#1September 22, 2011· Wizards of the Coast
You don't have priority between untapping Civilized Scholar and transforming it. You can't activate the draw-and-discard ability again, for example.
No other card is named in this ruling.
#2September 22, 2011· Wizards of the Coast
If Civilized Scholar attacks, and later in the turn (but before the beginning of your end step), it transforms, Homicidal Brute's last ability won't trigger. This is because the creature attacked that turn, even if had its other face up at the time.
No other card is named in this ruling.
#3September 22, 2011· Wizards of the Coast
You'll tap and transform Homicidal Brute even if it couldn't attack.
No other card is named in this ruling.