concrete floor on first floor flat

[alililley]

I am wanting to put down vinyl tiles in my kitchen and bathroom. Both have concrete floors. On the tile packet it says that I should put down a damp proof membrane, but is this likely to be necessary one floor up? Also, in the kitchen floor there is a hole, a crack and a slight lump in the concrete. There are kitchen units in place so I don't know if a self levelling compound would be a good idea. I was thinking maybe I could repair the hole and cracks with something and smooth out the lump somehow? There are currently vinyl tiles there, which are very old and knackered, but they seem to be pretty well stuck and no sign of a damp proof membrane, just some sort of paint on the concrete I think.

I'm a bit of a novice (obviously) so simple solutions would be the best.