I can answer this question myself at this point as I've just completed the practical last night.
@AndrejaKo provided a perfect example of the whole exercise in his video clip. Thanks also to the Essexham channel for that information.
It was simply a matter of:
- Calling CQ on the VHF calling frequency 145.500.
- Finding a clear frequency, checking it's clear then reporting that back to correspondent on calling frequency, requesting a QSY (frequency change) to the new frequency (using their call sign first each time before your own)
- Checking signal reports and QTH (location) with correspondent on new frequency and then finally clearing the frequency
You get an almost scripted sheet from your instructor, if you're lucky, as per the video and my own experience, and then you are guided through the call. It's just to show you can use the controls on a basic VHF set.
If you've been listening to any ham calls at all you'll be familiar with the format of the conversations. I went first, my associate second. I have been listening in for a year or more so was quite comfortable, if a little nervous at my first contact. He got through it just fine with no prior experience, obviously with a few more nerves from being bombarded by dozens of new and unfamiliar terms. But went over no trouble.
Hope that helps any new hams-to-be in the future.