New tropical fish tank help please

[feckingnora]

I just bought a 96L fish tank. I want to keep tropical fish. My mother keeps tropical fish, but is on holiday so I cant ask for her help.
I have got an air stone, a filter, gravel and ornaments. I have ordered a heater and it is on it way.
I have filled the tank with water and the filter and air stone are on. what next? obviously I need to wait for the heater before I can even think of fish, but what else do I need to do?
any help would be very appreciated!

Look up 'fishless cycling' - you need to populate the filter with bacteria.

Yep, fishless cycle will be your next step. While that's doing (takes around 4-6 weeks) you can plan what sort of fish you want to keep. 96 litres is a good size so will give you loads of options unless you water is really really hard.

This is a good explanation of fishless cycling.

I have just tested the water and the pH is between 7.5-8.2. nitrate is 0ppm and the ammonia is 0ppm.
are they good? or should I be trying to change them?

The ammonia will go up and then down again during the cycle. The nitrAte will go up and then you reduce it by doing water changes. pH is tricky to change but there are lots of lovely fish that will do just fine in alkaline water.