what we would do at the airport for 12 hours?

There will be 6 of us (not all of the same family) who will be stopping over for 12 hours on our way home to Australia after already having travelled from Europe. We will be landing in China at around 7 am and were wondering what we would do at the airport for 12 hours.

Is it worth going into the hotel to rest and freshen up / shower?

What is the lounge area I've read a bit about?

We're really not looking forward to this stopover as we will just be wanting to get home after 4 weeks of travelling and can imagine we would be very tired by this time.

Would really appreciate some practical advice from those who've been at this airport and had to wait for some hours between flights.

Thank you :)