I don't understand how can I connect to these characters and how can I have a connecter role (Leona and Sam) to our real life?
When you use words like "connect" and "connector" it sounds like you are participating in a literature circle with several other students in your class. Is this right?
In a literature circle the role of the connector is to draw connections between the book you are reading, in this case Seedfold, and your life, other books, or to the world in general.
It sounds like you are supposed to specifically draw connections between the characters of Leona and Sam, to yourself, "our real life."
I cannot speak for you, because I don't know who you are. However, I can speak for myself, and perhaps you can see an example of how connections can be made.
Sam is white, Jewish, and retired. I am not Jewish or retired, but I can connect to Sam because we both enjoy gardening. Because of Sam's age and health, he cannot garden on his own, and he has to hire someone to help him. I can connect with that, because I have an injury which prevents me from doing the gardening I would like to do. As you can see, I can connect with Sam on two levels. We both enjoy gardening and we both need help to do it.
Leona, on the other hand, is African American and is significantly younger than Sam. She plants a patch of goldenrod in memory of her grandmother. Leona takes the initiative to figure out how to get the City of Cleveland to take away the trash in the vacant lot. I am not African American, however I can connect with Leona's initiative to make change happen in her community. Her story reminds me of a time when I contacted the city offices where I live to convince them to plant trees on my street. It took some doing, but I made it happen.
Now, think about yourself. Knowing yourself and knowing the characters, think about ways in which you can connect to them. How do they remind you of yourself?