Flattery will get you everywhere!
Using the wax really shouldn't be a problem; assuming it's ours (most others are similar but avoid the ones designed for furniture use only, they're too slow drying) the trick is to apply the wax with a soft brush, then polish up soon after (about 30 seconds) with a stiffer brush. This will ensure that any surplus wax is removed by the stiffer bristles and this is easier to do before it dries hard.
A second coat can be applied if you wish in much the same way, leaving about fifteen minutes between coats.
Shoe brushes are good for this job, although we also supply bristle brushes that are slightly better as the bristle is specially chosen and gives the very best results.
(I know what you're thinking, :? but there really is a difference!)