Starting solid food

Baby had his 4 month checkup today and his pediatrician gave us the go ahead to start solid food. He's breastfed only. Nearly off the charts growth-wise, 99th percentile for height, 85th for weight. He has been showing interest in my food for over a month now (grabs food from my hand and I have to take it back quickly lol). He holds his head steady and sits up with some help, he still can't sit without something around him for a little back and side support.

Anyways, I wanted to see how other moms started solid food for their babies. Any apps, books, or websites you can recommend would be appreciated too!

Edit: Thank yall for commenting, I thought I've read other posts here saying that 6 months is the earliest to start, so we will definitely be waiting! Not the first time I've got bad advice about feeding from a pediatrician either unfortunately.