So, the questions are: is how does one become a delegate? Is it too late? The uncommitted ones are most likely GOPe beholding folks, but who will represent Trump or Cruz or Carson?
It varies from state to state. In some states, campaigns nominate a slate of delegates, in others, delegates have to win election. But the chances of a brokered convention are fairly slim. It’s a lot easier to write “this race is going down to the wire” than “tune in next July we’ll have a winner.”
You run for it, like a political office. I don’t remember all the details since my involvement in party politics was a while ago. Talk to your county chairman.