1. Fill the bigger holes with mortar.
2. Coat the floor with a couple of layers of bitumen paint (to stop
damp getting to adhesive/tiles - the whole floor wont be coated as the
areas under the kitchen units will be left).
3. Then use a leveling compound over the floor part to be tiled.
4. Apply tile adhesive and lay the ceramic tiles.

Treat the area with 1pva: 4 water before filling. A general purpose mortar
(Readymix etc) works well.
Forget the bitumen.
Use a latex screed (the one that comes with a liquid additive). I'd cover
the whole floor to 5mm thickness as you won't want damp getting up into the
units. Not the easiest stuff to work with though.
You could skip the screed and rely on the adhesive as a waterproofer but
using it to pack the tiles/level the floor can become expensive and will
take forever to dry. The latex is walkable in a couple of hours.