How to implement QGraphicsSceneDrag and Drop event. Qt Framework

Question

I'm making some project for university (checkers, if exactly).
I'm doing it with help of QtDesigner and in .ui file I have QGraphicsView that is my scene. The "ItemIsMovable" flag is set, of course. And I need to implement drag and drop of checker.

I'm trying to do it with QGraphicsSceneDragDropEvent. So I have two classes:

One that describes "Pawn"

class Pawn : public QObject, public QGraphicsEllipseItem {
    Q_OBJECT
private:
    QBrush kolor;
public:
    Pawn(int x, int y, int rozmiar);
    void dragEnterEvent(QGraphicsSceneDragDropEvent *event) override;
    void dragLeaveEvent(QGraphicsSceneDragDropEvent *event) override;
    void dropEvent(QGraphicsSceneDragDropEvent *event) override;
    void mousePressEvent(QGraphicsSceneMouseEvent *event) override;
};

And second, that describes one tile in board

class Tile : public QObject, public QGraphicsRectItem {
    Q_OBJECT
private:
    int x,y,row,col;
    QBrush color;
    Pawn *pawn;
public:
    Tile(QBrush color, int x, int y, int col, int row);
    bool isPawnSet();
    void setPawn(Pawn *pawn);
    void mousePressEvent(QGraphicsSceneMouseEvent *event) override;
};

So, when I drag and drop my pawn. No one of the Event methods is running(I have some QDebugs in them, so I know that nothing happens). I don't really know why. Because *event is passed as argument.

My question is, how to implement it in correct way? If you need more code, I will share it.