Well pretty straight forward really. Create a new buss and call it Headphones. The main concern is routing the outputs of that new buss to perhaps a spare set of analog outs so you can and then you can patch those into some sort of headphone amp. Or another option is to route the new buss to your main outs and stop everything else from going to your main outs. (during tracking only of course)
Now you can create sends on all of your tracks (at once too) and send them to your new buss. Don't forget any busses you may have set up eg drum buss or guitar buss etc can also send to your new buss. And even your main masterbuss can go there too if you want.
A few tips: Spend time getting a nice headphone mix. Musicians will love you for it (or you) and it just makes everyone (or you) play better, period. This is often rushed during a session. Slow down and get it right.
Don't be afraid to use the panning in your headphone buss. If you have got two guitars say pan them a bit to the left and right. It helps to distinguish them easier.
When tracking vocals dont let the bass get lost, keep it well up. It helps vocalists to pitch better.
Avoid heaps of reverb. It hides things and makes singers sound better than they are. You are better off keeping it a bit dry. It is hard but they will pitch a bit better as a result.
Don't have too much stuff happening in the phones when tracking. Keep it minimal. It helps you hear what you are tracking at the time better.
Often the drum overheads are enough to keep them in time maybe with a little kick and snare. Don't waste time trying to get all the toms in there as well. Not necessary.
You can create more than one headphone buss and create different mixes for people. But then you will need multiple analog outs in order to feed the diffeent headphone amp inputs etc..I have often found that one decent mix can do it most of the time!
Use decent headphones if you can and if you are listening in as well make sure you have got the same headphones that everybody else has. That way you are hearing exactly what they are hearing.
Hope that helps.
Where are you in Australia?