How to construct a branching program for a given function or formula?

Can someone throw some light on how to create a branching program from a given function? I have followed the definition of $BP$ on wiki and here. But I could not find any way to convert a function to $BP$.

P.S: I know $BP$ can be of exponential size for some functions. So any simple function on 3-4 variables will do for example $PARITY$ or $MAJ$.

• This site is for research-level question, which this is not. This would be a fine question for cs.stackexchange.com . – Emil Jeřábek Aug 7 at 9:11
• Ok thanks. I thought this is a good question for TCS. – chelsea Aug 7 at 9:14