Download the OpenWRT Breaking Barrier firmware for TP-Link WDR4300 router from http://wiki.openwrt.org/toh/tp-link/tl-wdr4300. You will also find the instructions on the upgrade process there.
Next, visit the web GUI interface of the TP-Link WDR-4300 router. In my case, this was at http://192.168.1.1 of the factory TP-Link firmware.
Select System Tools -> Firmware Upgrade, click on Browse… to select the breaking barrier firmware file and click on Upgrade. Wait for it to complete. You now have breaking barrier installed.
You can now log in to http://192.168.1.1 to set up the router using the web interface.
To administer OpenWRT via command line interface with ssh from your computer, you can type:
ssh email@example.com <enter>
Enter your password and you get to the OpenWRT router # prompt.
That’s all to installing the OpenWRT firmware onto the TP-Link WDR-4300 router.http://wiki.openwrt.org/toh/tp-link/tl-wdr4300