The first step consists in determinating exactly which work needs be done by identifying the nature of the floor covering present on the surface.
If the identification of a painted floor does not present any problem, the difference between a waxed or a varnished/sealed floor is not always obvious. The trick is to soak a cloth with Wax and Dirt Remover LOUIS XIII (for lack of, use white-spirit), and to rub the surface. If it gets coloured, the floor is waxed, if not it is varnished.

1- if the floor is waxed :

Remove the old layers of wax with Steel Wool LOUIS XIII N°2, soaked in Wax and Dirt Remover LOUIS XIII  (air the room thoroughly ), then sand until you recuperate the raw wood and thereby also eliminate any eventual under-coat or other transparent film which could prevent an even tint.

2- if the floor is dirty,varnished/sealed or painted :

Use Emulsion Stripper AVEL. Easy elimination of up to 10 coats of emulsions. Sand until recuperating the raw wood (floor sander). If necessary, dust off afterwards.