Food Advice for 10 month old!

Courtney
So my son will be 11 months on the 21st and he's a little behind on feeding himself and eating solid foods. He eats baby food just fine but will not eat any stage 3 that has chunks. When we give him some of our food 90% of the time he will just hold it in his mouth. He also doesn't pick any snacks up to feed himself. He isn't very interested in snacks either. He will eat maybe one or two puffs and a baby cookie here and there. He has 4 teeth but I don't think he knows how to use them. I'll sit with him and pretend to chew to show him but he still won't chew his food. His doctor said something about a therapist but I want to help him myself and not have to pay someone to do something I can do. We have a long road trip coming up since we are moving out of state and I want to be able to give him snacks to hold him over while we are driving. Any advice is welcome!! Thank you!