If I have viewed the correct antenna, it has only a single connection point, meaning, that even if it supports multiple bands, only one radio frequency channel can be connected to it with an N-male to SMA male cable.
The antenna itself can be connected to either one of the WiFi connectors on the router.
As for the configuration of the device, it depends on what are your use case requirements. The default configuration already has a pre-configured WiFi access point, anyone knowing its password can connect to.
If you want to impose more restrictions or to have monitoring and throughput control capabilities, consider configuring the following:
- A separate network for wireless clients, as instructed here;
- A hotspot instance. You can find an example with its configuration instructions here;