If he isn't interested in feeding and is grizzling a bit - take him out of his highchair and choose another time for him to have another go. It's more about playing and experimenting to start off with so keep it fun and don't worry if he doesn't eat very much (or at all).
Don't worry that they haven't got the hang of picking things like banana up straight away - it will happen very soon, babies are very fast learners
I used to try giving Jude banana with a band of the skin still on around the bottom to act as a sort of handle so he didn't squish it by squeezing too hard but then he would always end up picking it up at the wrong end or turning it over to eat the skin. Lol. Have seen other people do that successfully though. Another thing is to put a bit of it on a spoon and give the spoon to him to put in his mouth himself.
BLW is awesome - stick at it, the rewards are totally worth it