The key is to keep at it, but what I'd suggest is give him stuff at the same time you're eating if you can and just let him explore the textures, he'll put it in his mouth etc. That's all you can expect at this age tbh
Keep trying but also demonstrate what to do by eating at the same time. It does take them a little while to get used to it.
Takes babies 10 spoonfuls to get used to the taste. I would keep trying x