How to crack a code

[cherrycherry]

We are trying to crack a coded message with these letters:
BGMFRRRMAYJNIEPOOENAOUUY

The letters should fit into a grid, and the grids we have been given are:

(shape of grids)
12x2 squares, 12 down, 2 across
8x3 8 across 3 down
4x6 4 across 6 down
6x4 6 across 4 down
12x2 12 across 2 down
3x8 3 down, 8 across

We don't know even how to start working it out, so any help would be much appreciated.

[gen2]

The answer is on your other post here:

http://www.theanswerbank.co.uk/Quizzes-and-Puz zles/Question543951.html