Router mode functions as a typical router, connecting to the internet provided by your ISP and broadcasting a wireless signal, to create your own network.
Repeater mode lets you connect to your existing network and amplify it. This enables you to extend the range of your wireless network - invaluable if you have a weak connection in a room far away from your router.
The Mini Router can create a wireless connection from a wired source in Access Point mode. If only an ethernet port or ethernet cable is available, the router can connect to the wired connection and broadcast a wireless network that all your devices can connect to.
In Bridge mode, the Mini Router can connect to an existing wireless network and rebroadcast it under a new name; useful for organizing different users of your network into separate connections: e.g., if you ran a coffee shop and wanted to create a separate network name for your customers to connect to.
In Client mode, the Mini Router connects to a device such as a Smart TV or video game console using an ethernet cable and then can be used as a wireless adapter, enabling the connected device to connect to the internet wirelessly.