These are two different frequencies. They can be configured separately. You can configure only the 2.4 GHz frequency, only the 5 GHz frequency, or both. 2.4 GHz is the stronger signal, 5 GHz the weaker one (this is how an electrician/telematician explained it to me).

GIYF

Frequency band characteristics:
2.4 GHz WLAN network:
Longer range
More susceptible to interference, as technologies such as Bluetooth also use this frequency.
Very widespread. There can therefore be overlaps with the WLAN networks of neighbours.
Slower than the 5 GHz WLAN network

5 GHz WLAN network:
Slightly shorter range
More interference-free and therefore faster, especially over short distances
Less widespread
Ideal for bandwidth-intensive applications such as video transmission
More channels, some of which are regulated by DFS.

A few more additions:

The standard is also important. In order to benefit from the higher speed, especially 5 GHz, it is important that the ac standard is supported, which is the case with this repeater (with most current devices, but not yet by all).

And then there is the issue of SSID:
If you want to actively choose which band the devices connect to, you can give each band a separate SSID. If you want to leave the choice to the device, the same SSID can be used for both frequency bands.
Similarly, for the repeater, you can choose whether the repeater "keeps" the SSID or "repeats" with a different SSID.
I prefer to be able to see and choose the signal strength of the bands separately, as well as whether I choose the signal from the router or the repeater. Therefore I choose 4 different SSIDs (2x per band, separate SSIDs for the repeater).
So you can choose between 1 SSID (all the same - 2.4 GHz and 5GHz), 2 (only the frequency bands separately) or 4 (frequency bands separately as well as router and repeater separately).
Sorry to go into details here, but this question arises at the latest during configuration. And since every configuration makes sense depending on the application, it depends on where the devices are located and what one's own preferences are.

And to your further question: The 2.4 GHz signal is repeated with a 2.4 GHz signal, as is the 5 GHz signal with a 5 GHz signal.
Also, as far as I remember, you can only select one of the frequency bands during configuration (but not "map" one frequency band to another).
As far as I remember, for the LAN adapter you can choose which band is preferred if you are repeating a wireless signal to the LAN port, e.g. if you need the repeater to connect a device to a wireless network but this device only has LAN (and no WLAN).