US election 2016: Is the GOP headed towards a brokered convention?

A brokered convention occurs when no candidate secures the majority of delegates needed for a party's presidential nomination. In such cases, delegates are free to vote for any candidate after the first ballot. The process continues with multiple ballots until a candidate achieves the required majority. This was relevant in the 2016 Republican race, where 1237 out of 2472 delegates were needed to win the nomination.

What does it mean for delegates to be free to vote for whomever they want?

What is the process if no candidate gains a majority after multiple votes?