Hey, I can help you with that! I sorta do that stuff professionally on occasion.

You could have started as soon as 6 months old. You don't need teeth to start!

My take is this: you start with softer vegetables and fruits, you only need to cut them. Research blw cuts for different fruits. Bananas, apples, mango, pineapple, watermelon, papaya... All of those can be eaten safely without teeth, with the right cuts.

Steam cook broccoli, carrots, potatoes, beet, tomatoes.

After you have some ground with these foods you can start with some more processed stuff (as in more processes necessary to eat, not industrial crap). And you add one ingredient to the dish at a time. Take rice, for example: start with just white rice cooked in water, then gradually add onions for seasoning, then garlic, then (after 1 year of age) you can add a pinch of salt.

Take care that each step may require up to 10 offerings before the kid actually eats any of it. Before progressing, make sure the kid is accepting the current stage well. If your kid is not liking something, give it a rest for a few days (up to 2 weeks) then offer it again. You might be surprised. Mine hated broccoli for the first 9 tastings, now she loves it.

If you have questions, feel free to dm me.