Russia has formally launched a military operation in Ukraine. Dow futures are about 500 points off. Stocks are tanking. Gold and oil prices have spiked upwards. In these situations, it is more important than ever to keep your emotions in check, and avoid impulsive actions.
If you can stay logical, do read up as much as you can on this situation, and monitor news flow closely. It will help you determine what stocks to buy and sell, and also the timing to do so.
Conversely, if you feel that your emotions may cloud your judgment, please do the opposite and stay away from media reports on the markets. Do something to distract yourself. But try not to take too long to return to the markets. Opportunities may present themselves during this volatility that may not last long.
Do remember that in addition to asset prices fluctuations, there will also be some changes in stock/industry fundamentals. Thus it will be prudent to revisit the investment/trading cases for the stocks you already have or are interested in acquiring.
Good luck and stay sane!