Cath,
It's as easy as picking someone up from any airport. This July we collected my sister who flew in from Manchester via Chicago. We waited for her in the luggage collection area, met easily. We parked in the multi-storey car park which is linked to the terminal (can't remember which one), but as you drive in, all the airlines are listed telling you which terminal to go to. Just follow the signs. The car parks are signed also, telling you which aisle numbers to use for certain airlines.
Honestly, don't worry about it. It is very easy. Enjoy yourselves.
Pam