What we all dream of. To make sales on Amazon as a beginner is to focus on advertising to the right audience. Since your book is for children, having an attractive cover will go a long way during the advertising period. Kids love shiny things 😍.
By advertisement, I mean advertising to the right audience (kids), if you advertise to the wrong audience, you might not exactly make much money from the ads.
I wish you all the best 😊