In what mode should the Zyxel Keenetic router work?

I have a PC, a router Zyxel Keenetic Lite III, and an adapter TP-LINK TL WN722N, the back of the router has a lever that switches modes of operation, the modes are as follows – Main, Adapter, Amplifier, Access Point, to the router is connected only ethernet cable providerl, in the PC inserted adapter, in what mode should work my router for proper configuration and proper operation?

Answer

When you connect the cable from your ISP to the router, it should work in “Main” mode. It means that all services of the router are working. A couple of words about other modes:

Adapter – in this mode you can use the router to connect different devices to the Internet via a network cable. Zyxel Keenetic router will receive internet via Wi-Fi and transmit it to the device via cable.
Amplifier – in this mode, the router can amplify the signal of an existing Wi-Fi network.
Access point – extends the existing Wi-Fi network, but when connected to the main router not via Wi-Fi but via a network cable.

I think I have answered your question.