An overheating transmission is a real headache and needs to be addressed quickly! Stop the car and let the transmission rest for a while; don't force it to start, or it might "stop working."
Check the transmission fluid to see if it's low or dirty. If it's low, add more; if it's dirty, replace it, otherwise the cooling effect will be significantly reduced.
Also, check that the cooling system is functioning properly, such as checking if the radiator is clogged or if the fan is spinning. Problems with these small components can also cause the transmission to overheat.
If you can't fix it yourself, immediately visit a professional repair shop and have them perform a comprehensive "physical examination" of the transmission to identify the cause of the overheating and prescribe the right remedy!
In short, don't panic if your transmission overheats; calmness is key!