OK so you goofed a little no big deal....

Get some more soil or whatever your growing in and cover those seeds a little more. The last thing you want is your Roots exposed to too much light espically at that stage.As wll be careful those little seeds are very fragile at this stage so try not to move them at all just add a bit of soil ontop of em.

good luck and it wouldn't hurt to do a bit of reading seeing as you have beans in the soil now. You can never be too prepared when it comes to growing.

Its like anything Its easier to prevent a problem rather than fixing it after it has happened.

kd