The paragraph introduces Montag as someone who enjoys his work, and does not stop to think about what he is doing.
Montag imagines himself as a conductor in a symphony. He wants nothing more than to be in the fire, burning the books and contents of fireproof houses.
Montag grinned the fierce grin of all men singed and driven back by flame. (part one)
There are many metaphors used in the first paragraph. The second paragraph has more detail. There we learn that Montag takes pride in his work. He shines his helmet and hangs up his jacket neatly. He gets a rush from having faced fire and lived to tell about it. He also seems to enjoy the pure destructive power he has with fire.