To configure your TP-Link TL-WR902AC as a range extender, you can follow these steps:
Connect your computer to the router using an Ethernet cable, or connect to the router's wireless network.
Open a web browser and enter the default IP address of the router (192.168.0.1) in the address bar. Press Enter.
Enter the default username and password for the router (both are "admin" by default) and click "Login."
Click "Quick Setup" in the left menu and select "Range Extender Mode."
Select the Wi-Fi network you want to extend and enter the network password. Click "Next."
Follow the on-screen instructions to configure the range extender's wireless network settings, such as network name (SSID) and security settings (WPA2 is recommended).
Choose a location for the range extender where it can receive a strong Wi-Fi signal from the main router.
Connect the range extender to the main router using an Ethernet cable.
Click "Save" to apply the settings and restart the range extender.
Your TL-WR902AC should now be configured as a range extender. The range extender will broadcast a new Wi-Fi network with the same network name (SSID) and password as the main router, but with "Ext" added to the end of the network name. Connect your devices to the new Wi-Fi network to extend the range of your wireless network.