Customizable Map (Newbie question)

Hi all,

Please forgive this newbie question which I’m sure has been asked many times. However, I cant find an answer to my questions.

For my game I’d like the user to build his own map. The requirements are:

The user can create a map comprised of several tiles. The largest map would be a 5x5 grid, but smaller maps (e.g. 2x3, 2x4, 3x3 etc) are also possible.
Each tile has it’s own 5x5 grid.
The user must somehow “validade” the map to make sure that once the selection is finalized it can no longer be changed.

I don’t envisage controling pieces that move off the board, and I can create a deck of tiles which can be rotated and placed. My problems arise in aligning the tiles with the grid (essantially a max of 25x25) and validating the grid.

If you could point me in the directions of threads or examples I dont mind working on this off-line.

Thanks in advance,