Want to add a canvas in BorderPane, how? - javafx-8

Question

So im new to javaFX and want to make a borderpane with some buttons on the left and a canvas to draw lines with mouse in center.. on line 49 and 55 i get an error saying "cannot find symbol, variable scene".. why is that?
Please ignore my buttons, they are just there for show. Any other mistakes or pointers I would love aswell!
package simplepaint;
import javafx.scene.canvas.Canvas;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Button;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.geometry.Insets;
import javafx.scene.paint.Color;
public class SimplePaint extends Application {
Button but0, but1, but2, but3, but4, but5, but6;
#Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Simple paint");
//Creates all buttons
but0 = new Button("0"); //Create button - Line
but1 = new Button("1"); //Create button - rectangle
but2 = new Button("2"); //Create button - circle
but3 = new Button("3"); //Create button - move object backwards
but4 = new Button("4"); //Create button - Move object foreward
but5 = new Button("5"); //Create button - Move object backwards(1 spot)
but6 = new Button("6"); //Create button - Move object foreward (1 spot)
//Gives all buttons functions
but0.setOnAction(e -> System.out.println("Bro 0!"));
but1.setOnAction(e -> System.out.println("Bro 1!"));
but2.setOnAction(e -> System.out.println("Bro 2!"));
but3.setOnAction(e -> System.out.println("Bro 3!"));
but4.setOnAction(e -> System.out.println("Bro 4!"));
but5.setOnAction(e -> System.out.println("Bro 5!"));
but6.setOnAction(e -> System.out.println("Bro 6!"));
Canvas canvas = new Canvas(750,450); //Making draw window
GraphicsContext gc;
gc = canvas.getGraphicsContext2D();
gc.setStroke(Color.BLACK);
gc.setLineWidth(1);
/*Line 49*/ scene.setOnMousePressed (e -> {
gc.beginPath();
gc.lineTo(e.getSceneX(), e.getSceneY());
gc.stroke();
});
/*Line 55*/ scene.setOnMouseDragged (e -> {
gc.lineTo(e.getSceneX(), e.getSceneY());
gc.stroke();
});
VBox buttons = new VBox(3);
buttons.setPadding(new Insets(50, 10, 10, 10));
buttons.getChildren().addAll(but0, but1, but2, but3, but4, but5, but6); //Adds all the buttons on VBox
BorderPane bp = new BorderPane();
bp.setLeft(buttons); //Placing buttons on left
bp.setCenter(canvas); //Placing draw box in center
Scene scene = new Scene(bp, 800, 500);
primaryStage.setScene(scene);
primaryStage.show();
} public static void main(String[] args) {
Application.launch(args);
}
}