Create folder : Dataset
In Dataset folder create 2 folders : train and val Put training images in train folder and validation images in Val folder.
Download mrcnn folder from this repository: https://github.com/matterport/Mask_RCNN
Download coco weights : https://github.com/matterport/Mask_RCNN/releases/download/v2.0/mask_rcnn_coco.h5
Follow this video to understand the whole working: https://youtu.be/1u-dm5JMH1Q