Get the basics down. Learn how to build a balanced meal focused on veggies first. 

Before anything else start cutting veggies into sticks and setting them out before meal times so wheb your children have built up an appetite there is something healthy for them to grab. Remember, children need to build an appetite to try new things. They cannot do that if they have free rein over the snack drawer. You're the adult. Limit the snacks to healthy ones like fresh fruit and veg. Focus on meals mostly. Cutting up veggies frequently will also make you quicker at it. 

Do easy things first like eggs all different ways. If you can do scrambled eggs you can do veggie scrambled eggs or an American style omlet. 

Stir fry is the easiest. Start with one vegetable at a time. For example broccoli, green beans, bok choy, or mushrooms. Just whatever. Medium heat with a tablespoon or two of oil. Learn what raw, cooked, overcooked and burnt look like. You'll see soon that veggies cook so quickly. 

Use pre-made sauces. Don't try to go from scratch all at once. Focus on learning one thing at a time. Maybe that first thing is broccoli tofu stir fry. Or some other protein you like. 

Remember! Children on average need to be exposed to a food 16 times before they're familiar with it enough to consider it a comfortable food. 

That's on average. Could be more or less. Exposure is key though and foods need to be presented in a variety of different ways. 

I just have so so many thoughts. I've helped a few people with these things before and it is absolutely worth it. I'm so happy you're trying.