Is this words adjective of noun?

In the example:

In the phrase of ‘different bits of advice,’ is ‘bits of’ an adjective that means ‘trivial,’ or is bits a noun?

Ron also started teaching Harry wizard chess. This was exactly like Muggle chess except that the figures were alive, which made it a lot like directing troops in battle. Ron's set was very old and battered. Like everything else he owned, it had once belonged to someone else in his family -- in this case, his grandfather. However, old chessmen weren't a drawback at all. Ron knew them so well he never had trouble getting them to do what he wanted.
Harry played with chessmen Seamus Finnigan had lent him, and they didn't trust him at all. He wasn't a very good player yet and they kept shouting different bits of advice at him, which was confusing.