Law 7A: When a board is to be played it is placed in the centre of the table till play is completed.

Quite simple really – do not remove the board from the table, do not move it to the side so that it cannot be seen, do not turn it through 90◦. Just leave it in the centre of the table!
(It is all right to move it a short distance to accommodate dummy, but it MUST stay where it can be clearly seen by all 4 players, with the compass signs pointing towards the correct players.)

The aim is to cut down the risk of someone returning a hand to the wrong slot, creating extra work for the scorer, or making it impossible for the board to be scored, and so spoiling the tournament.

Also, players are entitled to check the vulnerability and dealer during the course of play.

Associated Recommendation:

Place just one board on the table at a time.

This makes it easier to score, and stops the unfortunate confusion when one player takes a hand from one board and the other three players take their hands from another..... you think that never happens??