I break down several ways i like to work on red market days:

Research The companies im holding (to see who will pop or fall) or want to hold next

Learn different indicators or strategies or trading sectors (ie Futures, forex, options etc.

PLUS much more, especially if you scan the screen for info too!

BONUS - The video I'm about to play at the end is another GEM from Humbled Trader on YT on indicators that are commonly used - Macd, VWAP, RSI and 1 more . I've linked it below.