I personally would start by developing the characters as far out as possible. Know them better than you already do. Then, you can take the main points from your book and make a short cartoon out of each separate point. The more well developed your characters are, the more stories you can get out of them. I'm not sure what age range this book is for, but you could have the plot of one episode be sharing or friendship or the golden rule. Try watching qubo as well. You can get a lot of general ideas for different episodes and just plug your characters into that.