This automated process usually takes a few moments but manually syncing the apps requires adding the IP address and username. Once installed, they will need to be synced to transfer the images and audio between each device.
This means that if you want to view content from your Android phone or on your desktop monitor, you'll need the sender app. The receiver will be the device that accepts input from the sender. Firstly decide which device will be sending and which will be receiving.
You will need to download both the sender and receiver applications for you to cast between the device and monitor. This program involves a two-step process.