Srinija Sirobhushanam takes us through some of the key concepts around convolutional neural networks:
How are convolution layer operations useful?
CNN helps us look for specific localized image features like the edges in the image that we can use later in the network Initial layers to detect simple patterns, such as horizontal and vertical edges in an image; and deeper layers detect complex patterns.
This is a rather high-level description of the topic, but it serves to give an understanding of what you need to know before building and using these networks.