What's the model number of your extender? It may be that your computer connects to your router not the tplink network. By the way, the extender has the same password as your router. Is it because...

Is WA500G an old model? I cannot find it on tplink website. Make sure you install the latest firmware

models like Archer C2300, C3150, C5400 can handle wireless schedule. If you want tplink to add it to 841N, feedback to tplink support

You cannot login the admin page of the router? Did you try login from another device? Or reboot/reset your router? Do not connect any other modem to the tplink and try login. If it's in, you can...

You can go with the nnfostrada 1 since the parameters are the ones your ISP give you. You can change the encapsulation during the setup wizard. And where do you see the parameters change. There are...

If you want to setup mac filtering, you may need to find out the mac address of the extender. http://www.tp-link.com/en/faq-927.html