"admin01" password, which you changed other Ethernet cable is related with device's WebUI. I.e. it is used to access device's WebUI, from which you can configure your device or see its status.
Meanwhile, to connect your phone to router's WiFi, you would need to use separate password, which is written on the sticker (or engraved with laser) on the back of the router. Each router has unique WiFi password for security reasons. Another method would be to connect to router's WebUI through Ethernet cable again and navigate to "Network -> Wireless -> (edit)" menu. In this menu you would be able to see and change default WiFi password.
Once your phone will be connected to router's WiFi, you should be able to access router's local IP address through phone web browser (IP: 192.168.1.1) and connect to router's WebUI with same "admin01" password (just with actual password, to which you changed WebUI password)