I allowed my son to play with his toys how he wanted. I played along side of him, I would build tall towers, he would have fun knocking them down. I never realized I helped him, but I did, by modeling how to do things the right way. Eventually he wanted to do what I did, so he would grab my hand and push me to build towers for him. He was nonverbal back then, but I still knew what he wanted me to do. Then he learned how to do it on his own. It took time, and it’s fine. The same thing happened with his transformers, he loved throwing them up and watching them fall. I would do the same thing he was doing to engage and be a part of his world, I forced myself in. Have fun with him, he can sense if you’re stressed or irritated with him. Try not to worry, connect with him.

Don’t try to show him what to do. Play beside him and imitate what he’s doing. It may not make sense to you but it does to him. Slowly you’ll start understanding where he’s coming from. Eventually you can try some playful obstruction to get a reaction from him. Here’s a YouTube link to Dr.Greenspan’s floortime to give you an idea for playful obstruction. But the key is to first gain his trust by playing beside him and doing what he’s doing... if it’s lining up toys, you line up along side his...

https://m.youtube.com/watch?v=Gobbe0zqsDE

There are plenty of floortime videos and talks on YouTube.

I second that. Just let him play his way unless it gets unsafe. Mine likes to throw her toys.
Sometimes at us, but alwas with a smile on her face.

enter his world and have fun with him. Appropriate play is BS. Mine used to do the same, now can play board games without any issues.

If he is upset when you try and interact with him it may be bc he has things exactly how he wants them...maybe parallel play with him to start...make your own line of toys or stack blocks near him ( not in his personal space)...try and show him your cool line of cars and small toys or your awesome tower of blocks and see if he wants to add to your piles rather then changing his line or tower...its a great starting piont..we did this, and still do this but my son is more engaging each day.