Laying Victorian Quarry Tiles on Earth - Tile Advice

[robboy]

Hello,

I've removed a door in my kitchen and I'm planning on tiling over the area.
It looks like the rest of the floor has been taken up at some point and a concrete and DPM put in before re-installing the quarry tiles.
The area under the wall is straight onto earth. I want to tile over this area with some spare tiles I have as the two side line up.
Can anyone suggst the most sensible way to do this?
Can I just patch in a DPM and concrete and then tile on top? How deep should I go the the concrete?
Damp isn't a problem in the house if that makes any difference.
Thanks.

 

[robboy]

Also what's the best adhesive and grout for quarry tiles. Thanks