How much solids should my 11 month old be eating a day?

He’s almost 12 months. Right now he has breakfast, lunch, and dinner, along with breast milk. He’s still not sleeping through the night! I worry that maybe I’m just not feeding him enough during the day? Should he be having snacks as well?

I just want to know how much food should be on his plate, how often, etc. I’m a first time mom so I honestly know nothing 🤦🏻‍♀️