Simple way to run two while loops at the same time using threading?

Simple way to run two while loops at the same time using threading?

I have looked through all the previous answers, and they are all too
complicated for a beginner like me. I want to run too while loops at the
same time. For example, I want to run these two at the same time:
def firstFunction():
do things
def secondFunction():
do some other things
As I said, the other answers are too complex for me to understand.