Stay away from bonks and mind-straining activities, but do other things including light (aerobic, not anaerobic) exercise. Increasing toward your previous levels over time.

I would add to this: If you’re a clumsy person who trips on treadmills, maybe walking on a treadmill should not be in the cards for you.

except: 1) avoid the possibility of head injuries, and 2) if you suffer more than slight symptoms from daily routine, dial it back

I had a pretty bad concussion when I was very young and I still remember how distorted my short term memory was right afterwards and to a lesser extent weeks after. Couldn't imagine trying to be active nowadays under those circumstances.