There are different web UI for differnet routers. You can put key words on the the tplink official website to search the proper instruction for your model....

It's better to provide a error screenshot of the kasa app. Besides, what's the OS version on Note 8? Have you tried removing the kasa app and reinstalling it?

Accroding to the alexa command instruction, it looks like it does not support this command so far. https://www.tp-link.com/us/faq-1356.html This is a good feature and hope it will be added.

Firstly, make sure your modem's Wi-Fi is working properly. Then, try to refer to the instruction to configure the extender. https://www.tp-link.com/en/faq-1400.html If that's different from your...

In that case, you may connect your pc directly into wall box to see whether it work. if it's not, you may need to set pppoe connection on TPlink router to put the AT&T username and password. It seems...

Different hardware versions cant' be updated. Therefore, we can't update firmware of V13 on your V9 device.