Board Game Arena

Total newbie question. I played for the first time the other day and was able to select the colors but was unable to make them drop. Don't you just select with mouse and that is it? What was I doing wrong? Game timed out and i was warned for leaving a game early...so frustrating. Tutorial is vague and play through just selects and they fall.
Thanks for any suggestions.
_D

Did you hit any button after selecting the pieces, in the top bar?