How to manage multiple screen in kivy? - python-2.7

Question

I am using kivy to scan cards.How do I manage multiple screens . I wanted to capture the card first and the captured card should be passed to tesseract?
from kivy.app import App
from kivy.lang import Builder
import time
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from PIL import Image, ImageEnhance, ImageFilter
import pytesseract
from kivy.uix.button import Button
Builder.load_string("""
<CameraClick>:
orientation: 'vertical'
Camera:
id: camera
resolution: (640, 480)
play: False
ToggleButton:
text: 'Play'
on_press: camera.play = not camera.play
size_hint_y: None
height: '48dp'
Button:
text: 'Capture'
size_hint_y: None
height: '48dp'
on_press: root.capture()
<SettingsScreen>:
BoxLayout:
Button:
text: 'My settings button'
Button:
text: 'Back to menu'
on_press: root.manager.current = 'menu'
""")
class CameraClick(BoxLayout):
def capture(self):
'''
Function to capture the images and give them the names
according to their captured time and date.
'''
camera = self.ids['camera']
timestr = time.strftime("%Y%m%d_%H%M%S")
camera.export_to_png("reading.png".format(timestr))
print("Captured")
class SettingsScreen(Screen):
def card(self):
im = Image.open(r"readimg.png")
p = pytesseract.image_to_string(im, lang='eng', config='-psm 6')
print p
return Button(text=p)
# Create the screen manager
sm = ScreenManager()
sm.add_widget(CameraClick(name='menu'))
sm.add_widget(SettingsScreen(name='settings'))
class TestApp(App):
def build(self):
return sm
if __name__ == '__main__':
TestApp().run()
I am new to kivy I wanted to know how to manage multiple screens.How to display the content of the card from tesseract in another screen?