Questions about coolant temp sensor replacement.

There is a drain on bottom of rad. I usually don't drain any make sure engine is cold leave rad cap on slowly remove sensor have new sensor ready once removed quickly screw in new senor by hand once started the tighten with socket. Leaving the rad cap on minimizes coolant loss. Make sure u have a pain under engine.

Plug in new sensor remove rid cap start engine top up coolant let run tell u have good heat make sure coolant leval is full reinstall cap

Do I need any Teflon tape or anything for the threads on the new sensor?

Usualy there is sealant on new part if not then yes I would use some Teflon tape