The head of the Wheelbarrow family is one of the toughest of the bunch, and might not be the best to start with if you have any doubts on your strength and endurance. For those who are capable, we recommend for the woman to get into a downward dog yoga position, with the man approaching from behind. Once there, he should wrap his hands around her thighs, and then lift her legs into position.
Some may prefer to 'dock' (penetrate) before lifting the legs, as once in position, there isn't a hand left to assist for aiming, and for related reasons, it's generally best to keep the strokes a little shorter, as slipping out can be more difficult to fix when airborne. Extreme height differences can be overcome with anything from couch cushions to stairs, but the latter is much less friendly to a crash landing. If you're going to try out something like a chair, make sure it is very stable before taking a chance on it!