Quoted from Black_Knight:

Congrats on your first machine! Why would you want to take it off free play? Most new owners talk about it, some do it, but they all seem to put it back on free play after a while.
Look at the small square by the 3rd player. The # of credits is printed on the credit wheel that moves.
If you didn't know that, you may not be ready to dive in and make the change right now.
Play it for a while and enjoy it. Don't risk messing something up this early in your ownership, that's why a lot of people get frustrated with pinball.
If you still want to make it coin op in a month, then we can walk you through it.