@cmkubli described the process well. However, my keyboard was disconnecting frequently and by changing the battery that came with the keyboard, everything worked better. I have the impression that the battery included by Logitech is not at full capacity.

There are 3 grey buttons on the top left of the keyboard, if you press one of them long enough the pairing process should start. If you switch on Bluetooth on the Galaxy Tab and stay on the button longer, it should show you all available devices, then you can pair.

The battery issue depends on how long you've had the device. If it is new, you still have to release the (button) battery (pull off the strip)

I also had it once. The battery was flat 😉

unfortunately not, galaxus/digitec support may be able to help