It seems appropriate to begin at the beginning. Though, of course, as new discoveries come to light the beginning may be pushed further back in time. The great games expert HJR Murray (author of the incomparable History of Chess), in his second major book, the History of Board Games other than Chess, said that:

By chance I happen to live in Brussels, and so here is a picture that I took of the actual board:

El-Mahasna board, Brussels

Nothing can be known about the game played on the board, or if it is related to any later game in Egypt or elsewhere. It appears to have a 3-by-x layout, which is similar to other known boards such as the Game of 30 Squares, but that may be coincidence. We will probably never know anything more about this game.