To cast your phone screen on your TV you need to have Chromecast.
Follow the steps to successfully cast your screen-
Before you begin casting
Cast from Chromecast-enabled apps to your TV
Note: The Cast button isn't located in the same place on all Chromecast-enabled apps.
You can now cast videos, movies and TV shows directly to your TV.
To stop casting, tap the Cast button and then Disconnect.
You can also watch this step-by-step guide to do the same
You can check more details here : Oppo F11
Oppo F11 does not major heating problems as such. If it is getting heated up while playing games for longer, overcharging or using animate wallpapers and widgets. It is actually finally and nothing to worry.
To avoid this you should not use a plastic cover and turn off Bluetooth, Location, Wi-Fi and network when not in use. However, if that is not the case, it might be due to presence of malware in your device. For the same, you must install and use "Junk Cleaner" and an Antivirus. Trying resetting your phone.
You can see detailed specs here: Oppo F11