Do you know when McDonald's was founded?
Yes MacDonald's was founded in 1940 as a restauran operated by the McDonalds brothers.
How did Ray Kroc come into it?
In 1955 Ray Kroc joined the company as a franchise agent and later bought the chain from the brothers.
What is a franchise agent?
Someone who operated a franchise and sell franchise to other people,  Did you watch the movie "The Founder" about how the chain was developed?
No, but I would like to.   Who was the star?
I don't remember his name, but I enjoyed the film and would recommend you watch it.  
I think it was the guy who played Batman in the eighties.
Maybe.  McDonald was very innovative when founded but has suffered a backs;ash in recent years, for the alleged unhealthiness of its food.